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A  SYSTEM       V,n  XX 


CHEMISTRY  APPLIED 


DYEING. 

BY 

JAMES  NAPIER,  F.  C.  S. 
A  NEW  AND  THOROUGHLY  REVISED  EDITION, 

COMPLETELY  BROUGHT  UP  TO  THE  PRESENT  STATE  OF  THE  SCIENCE, 

INCLUDING  THE 

CHEMISTRY  OF  COAL  TAR  COLORS. 

BY 

A.  A.  FESQUBT, 

CHEMIST  AND  ENGINEER. 
WITH  AN 

APPENDIX 

ON  DYEING  AND  CALICO  PRINTING 

AS  SHOWN  IN  THE  UNIVERSAL  EXPOSITION,  PARIS,  1867. 


ILLUSTRATED. 

1 1>  $  I 


PHILADELPHIA: 
HENRY    CAREY  BAIRD, 

INDUSTRIAL  PUBLISHER, 
406  Walnut  Street. 
1869. 


TP 


c,  \ 


Entered  according  to  Act  of  Congress,  in  the  year  1869,  by 

HENRY    CAREY  BAIRD, 

in  the  Clerk's  Office  of  the  District  Court  of  the  United  States  in  and  for  the 
Eastern  District  of  the  State  of  Pennsylvania. 


PHILADELPHIA  : 
COLLINS,  PRINTER,  705  JAYNE  STREET. 


THE  GETTY  CENTO?? 
LIBRARY 


SECOND 


PREFACE 

TO  THE 

AMERICAN  EDITION. 


Napier's  System  of  Chemistry  Applied  to  Dyeing 
fills  a  place  in  the  literature  of  dyeing,  which  no  other 
book  in  the  English  language,  with  which  we  are  ac- 
quainted, does.  It  has  passed  through  an  edition  each 
in  the  United  States  and  in  England,  and  has  for  some 
time  been  out  of  print  in  both  countries.  A  steady  and 
pressing  demand  for  it  here,  may  be  taken  as  conclusive 
evidence  of  its  usefulness,  and  of  the  estimation  in  which 
it  is  held.  That  it  is  a  book  of  great  value,  there  can 
be  no  question. 

The  present  edition  has  been  carefully  revised  and 
edited  throughout  by  Professor  Fesquet,  who  has  made 
very  many  additions  to  it,  especially  upon  the  important 
subject  of  Coal  Tar  Colors;  and  it  is  presented  to  the 
American  public  with  every  feeling  of  confidence  that  it 
will  be  found  to  give  a  faithful  view  of  the  present 
state  of  the  Science  of  Chemistry,  from  the  dyer's  stand- 
point. 

A  full  and  carefully  prepared  index  is  added ;  which 
will  render  reference  to  any  subject  in  the  volume  easy 
and  expeditious. 

H.  C.  B. 

Philadelphia,  January  28,  1869, 


PREFACE  TO  THE  LONDON  EDITION. 


If  there  be  any  trade  which,  more  than  another,  requires 
the  knowledge  of  first  principles,  it  is  that  of  dyeing,  it  being 
essentially  progressive.  The  particular  conditions  of  the  trade 
render  information  of  this  description  more  needful,  and  there- 
fore more  valuable,  than  ordinary.  The  trade  is  what  is  termed 
open,  so  that  any  man  may  enter  it ;  and,  in  consequence, 
there  are  few  instances  where  young  men  are  taught  the  busi- 
ness systematically.  A  great  many  enter  the  trade  who  are 
grown  up — their  chief  ambition  being  to  learn  the  mechani- 
cal operations  of  the  dye-house,  and  when  sufficient  dexterity  in 
these  is  attained,  to  secure  the  highest  rate  of  wages.  When 
this  is  accomplished,  zeal  for  improvement  in  a  great  measure 
subsides.  However,  there  are  many  who,  not  content  with 
acquiring  a  knowledge  of  the  mere  mechanical  routine,  desire 
to  look  deeper  into  the  principles  of  the  art,  and  aim  at  higher 
honors  than  those  of  a  mere  laborer  in  it,  but  who  believe 
that  the  means  of  success  consist  simply  in  long  and  steady 
service,  and  a  good  memory  for  the  rules  of  manipulation. 
Both  of  these  are  valuable  qualifications,  but  neither  of  them 
would  be  depreciated  in  the  slightest  degree  by  being  conjoined 
with  a  more  extended  knowledge  of  the  fundamental  princi- 
ples of  the  art  than  usually  falls  to  the  share  of  the  practical 
dyer.  There  is  another  evil  arising  out  of  this  condition  of 
the  trade.  Individuals  who  attain  the  position  of  good  work- 
men, value  their  abilities  by  the  contrast  which  exists  between 


VI  PREFACE  TO  THE  LONDON  EDITION. 

them  and  the  newly-initiated  journeyman  ;  but  they  rarely  or 
never  look  forward  to  the  wide  field  which  lies  unexplored 
before  them.  Often,  indeed,  they  boast  of  their  capabilities,  of 
their  expertness,  and  their  knowledge ;  and  it  is  no  uncommon 
thing  for  them  to  indulge  in  petty  jealousy,  and  endeavor  to 
conceal  the  secret  of  their  mode  of  working  from  their  neigh- 
bors. Under  these  circumstances,  it  is  no  wonder  that  years 
are  often  spent — we  should  say  wasted — in  endeavoring  to 
discover  what  was  long  before  patent  to  every  one  who  knew 
the  scientific  principles  of  the  trade,  although  ignorant  of  the 
practical  operations  of  it.  This  ignorance  of  principles  often 
makes  both  workman  and  master  the  dupes  of  knaves  who  go 
about  hawking  valuable  secrets  at  so  much  apiece. 

It  must  be  admitted,  however,  that  notwithstanding  all  un- 
toward circumstances,  the  degree  of  advancement  which  the 
art  has  attained  is  truly  astonishing.  A  single  practical  hint 
is  sometimes  sufficient  to  cause  a  complete  revolution  in  some 
branch  of  the  trade,  so  that  were  the  principles  of  chemistry 
in  their  application  to  dyeing  but  once  generally  understood 
by  those  practically  employed,  we  can  hardly  conceive  what 
changes  and  improvements  might  not  be  effected. 

Another  circumstance  calling  for.  a  few  remarks  is  the  fluc- 
tuating state  of  the  trade,  which,  even  in  its  best  condition, 
throws  not  less  than  a  fourth  part  of  the  workmen  idle  during 
the  winter  months.  But  while  we  admit  the  hardship  of 
such  a  state  of  things  in  its  fullest  extent,  we  do  not  believe 
that  this  time  should  be  allowed  to  glide  by  in  absolute  list- 
lessness.  It  is  still  a  portion  of  the  allotted  span  of  life,  and 
ought  to  be  turned  to  all  the  advantage  which  circumstances 
will  admit;  and  if  it  can  be  made  subservient  to  future  ad- 
vantage either  by  advancing  the  personal  interests,  or  in  aug- 
menting the  mental  enjoyment,  of  the  individual,  it  is  surely 
culpable  to  allow  it  to  run  to  waste.  We  sincerely  believe 
that  it  may  be  turned  to  account  in  both  ways,  and  we  promise 


PREFACE  TO  THE  LONDON  EDITION.  vii 

with  some  confidence  that  the  following  Treatise  will  suggest 
the  means  of  deriving  remuneration  even  from  idle  hours. 
Lord  Bacon's  maxim,  that  "  Knowledge  is  power,"  has  been 
reiterated  till  it  may  be  thought  to  have  lost  its  virtue,  but  it 
is  still  as  true  as  ever,  and  we  are  confident  that  it  cannot  be 
more  aptly  applied  than  to  the  case  of  the  practical  dyer. 

From  our  own  experience  we  are  aware  that  there  at 
present  exists  a  strong  desire  amongst  a  great  many  of  those 
employed  in  the  processes  of  dyeing  to  understand  the  prin- 
ciples of  the  art,  and  to  be  able  to  assign  reasons  for  the 
various  changes  that  take  place  in  producing  the  colors.  Such 
knowledge  is  often  eagerly  sought  for  without  success,  both 
in  books  and  in  the  lecture-room.  The  disappointment  arises 
from  two  sources :  first,  the  inability  of  the  dyer  to  apply 
chemical  principles  to  his  special  purposes ;  and  second,  a 
want  of  practical  knowledge  in  the  author  or  lecturer,  which 
disqualifies  him  for  pointing  out  the  special  applications  of 
the  principles  he  may  be  defining.  These  circumstances  have 
long  impressed  the  Author  with  the  opinion  that  an  applica- 
tion of  principles  to  any  practical  operation  can  best  be  done 
by  an  individual  working  at,  or  familiar  with,  all  the  practical 
details  of  that  particular  operation  or  trade,  and  that  every 
branch  of  trade  or  art  ought  to  have  its  own  guide-book  pre- 
pared by  one  of  its  own  operatives.  The  carrying  out  of  this 
idea  has  induced  the  Author  to  publish  the  present  Manual, 
which  is  a  "System  of  Chemistry  applied  to  Dyeing." 
Having  been  himself  a  practical  dyer  for  many  years,  and 
having  experienced  the  difficulties  which  an  uneducated  man 
has  to  contend  with  in  striving  to  become  a  Dyer  in  the  proper 
sense  of  the  term,  he  has  in  the  following  pages  endeavored  to 
clear  away  some  of  the  technical  difficulties  besetting  the  path 
of  the  practical  man,  and  to  guide  him  in  following  out  first 
principles  while  engaged  in  experiments  to  advance  his  art. 

The  Author  acknowledges  his  obligations  to  a  few  intelligent 


viii 


PREFACE  TO  THE  LONDON  EDITION. 


dyers  for  several  practical  hints  contained  in  these  pages,  and 
which  had  not  come  under  his  own  observation.  It  will  also 
be  seen  in  reading  the  work,  that  advantage  has  been  taken  of 
some  valuable  articles  in  foreign  journals,  translations  of  some 
of  which  have  appeared  in  chemical  periodicals,  such  as  the 
Pharmaceutical  Times,  which  is  now  discontinued,  and  the 
Chemical  Gazette,  a  journal  which  he  earnestly  recommends  to 
the  practical  dyer,  as  containing  from  time  to  time  papers  of 
great  value  upon  Dyeing  and  Dye-stuffs. 

Partick,  Glasgow. 


i 


CONTENTS. 


GENERAL  PROPERTIES  OF  MATTER. 


HEAT. 

PAGE 

Conditions  of  Matter   17 

Heat  the  cause  of  Conditions  of  Matter   17 

General  Effects  of  Heat   19 

Measures  of  Temperature   19 

Boiling  of  Liquids   21 

Substances  affecting  Boiling  Point   21 

Strong  Boiling   22 

Chemical  Effects  of  Heat  upon  Colors   23 

LIGHT. 

Nature  of  Light        .       .  .25 

Relation  of  Colors  to  the  Fabric   26 

Effects  of  Different  Rays  upon  Colors       .       .       .  '    .       .  .27 

Effects  of  Light  causing  Combination       ......  28 

Light  Decomposes  Chemical  Compounds   29 

Practical  Application  of  the  Principles   30 

Harmonizing  Colors   32 

ELEMENTS  OF  MATTER. 

Differences  between  an  Element  and  Compound        ....  34 

Use  of  Symbols   36 

Nomenclature   37 

Rules  for  Naming  Compounds   37 

Salts — Their  Nature  and  Nomenclature   39 

CHEMICAL  AFFINITY. 

Application  of  Affinity   42 

Circumstances  influencing  Affinity   42 

Catalytic  Influence   43 

Constitution  of  Salts   44 

Salt  Radicals   45 


X  CONTENTS, 


ELEMENTARY  SUBSTANCES. 

PAGE 

Oxygen  ' .       .       .  .47 

How  to  make  Oxygen  Gas   48 

Properties  of  Oxygen  49 

Hydrogen  .49 

Water        .      .  .50 

Bin-oxide  of  Hydrogen  58 

Nitrogen  .       .       .  .       .  .58 

Protoxide  of  Nitrogen  60 

Binoxide  of  Nitrogen  60 

Nitrous  Acid  61 

Peroxide  of  Nitrogen  61 

Nitric  Acid  61 

Table  of  the  Quantity  of  Acids  in  100  parts  by  weight       .       .  65 

Ammonia  67 

Chlorine  68 

Hypochlorous  Acid   .  .69 

Hypochloric  Acid  69 

Chloric  Acid  70 

Hyperchloric  Acid      .  70 

Hydrochloric  Acid  70 

Chloride  of  Nitrogen  \  .74 

Bleaching  75 

Ozone  ......      .      .      .      .      .      .  93 

Sulphur  93 

Sulphurous  Acid  94 

Sulphuric  Acid  95 

Hyposulphurous  Acid         ........  100 

Hyposulphuric  Acid  101 

Sulphureted  Hydrogen  10L 

Selenium  103 

Phosphorus  103 

Iodine   .  .       .       .       .  104 

Bromine  105 

Fluorine  105 

Silicium   106 

Boron   106 

Carbon  106 

Carbonic  Oxide  108 

Carbonic  Acid    .       .       .  108 

Oxalic  Acid  109 

Cyanogen  110 

Mellon  Ill 


CONTENTS.  xi 
METALLIC  SUBSTANCES. 

PAGE 

General  Properties  of  Metals   112 

Potassium   113 

Potash  .113 

Sulphate  of  Potash   117 

Bisulphate  of  Potash  #            .       .       .  117 

Sulphite  of  Potash  „      .      .  .118 

Nitrate  of  Potash   118 

Chlorate  of  Potash     .       .       .   118 

Phosphate  of  Potash   118 

Oxalate  of  Potash      .   118 

Ferrocyanide  of  Potassium   119 

Ferricyanide  of  Potassium   122 

Cyanide  of  Potassium        ........  123 

Cyanate  of  Potash   123 

Sodium                                                                              ..  123 

Soda    ...       .      .   124 

Soda-Ash  .125 

Sulphate  of  Soda   129 

Chloride  of  Sodium   130 

Nitrate  of  Soda   130 

Borate  of  Soda   130 

Phosphate  of  Soda   130 

Lithium      .      .   130 

Soap   131 

Barium                                                             .       .       .       .  134 

Strontium   135 

Calcium                                                                       .      .  135 

Caustic  Lime                                                                   .  135 

Sulphate  of  Lime  •  .  136 

Carbonate  of  Lime   136 

Magnesium  #   136 

Magnesia  .136 

Aluminum  .       .       .       .       .   137 

Alumina   137 

Alum   137 

Sulphate  of  Alumina   141 

Alum  Cake                                                              .      .  141 

Aluminate  of  Soda     .........  141 

Acetate  of  Alumina   141 

Manganese        .   149 

Mineral  Cameleon      .........  150 

Iron   151 

Sulphate  of  Iron   152 

Chloride  of  Iron        ....      .       .      .      .  .157 


Xll 


CONTENTS. 


PAGE 

Carbonate  of  Iron      .   157 

Acetate  of  Iron   157 

Persulphate  of  Iron   158 

Nitrate  of  Iron  .       .  \    .       .       .       .       .       .       .       .  158 

Protosalts   161 

Persalts  of  Iron   .  162 

Cobalt     !   162 

Nickel  •   163 

Sulphate  of  Nickel     .       .       .       .   164 

Chloride  of  Nickel   164 

Nitrate  of  Nickel   164 

Carbonate  of  Nickel   164 

Zinc   164 

Chloride  of  Zinc   165 

Sulphate  of  Zinc   165 

Nitrate  of  Zinc   165 

Cadmium    .      .       .   166 

Copper      .       .      .       .      .       .       .   167 

Protoxide  of  Copper   167 

Sulphate  of  Copper   168 

Nitrate  of  Copper   168 

Chloride  of  Copper     .    168 

Acetate  of  Copper      .       .       .       .   169 

Oxalate  of  Copper   169 

Arseniate  and  the  Arsenite  of  Copper   169 

Lead  .     .  .  169 

Suboxide  of  Lead   170 

Protoxide  of  Lead      .........  170 

Peroxide  of  Lead   171 

Carbonate  of  Lead      .........  171 

Nitrate  of  Lead   171 

Acetate  of  Lead   171 

Sulphate  of  Lead   173 

Chloride  of  Lead   173 

Testing  the  Value  of  Lead  Salts   ]  74 

Bismuth   .       .       .    '  .       .  174 

Nitrate  of  Bismuth   175 

Tin   175 

Protoxide  of  Tin   177 

Protochloride  of  Tin  (Salts  of  Tin)   17 

Protosulphate  of  Tin   178 

Protonitrate  of  Tin   178 

Tartrate  of  Potash  and  Tin   178 

Stanno-Arsenite  of  Soda   178 

Deutoxide  or  Sesquioxide  of  Tin   17 

Peroxide  of  Tin   179 


CONTENTS.  Xlii 

PAGE 

Perchloride  of  Tin   180 

Spirits   181 

Red  Spirits   182 

Plumb  Spirits   183 

Barwood  Spirits   183 

Yellow  Spirits   183 

Acetate  of  Tin   183 

Oxalate  of  Tin   183 

Titanium   184 

Chromium   185 

Chloride  of  Chromium   186 

Sulphate  of  Chromium       ........  186 

Chromic  Acid   187 

Bichromate  (Red  Chromate)  of  Potash      .       .       .      .       .  188 

Chromate  of  Lead   189 

Chrome  Yellow   189 

Chrome  Greens   .       .   191 

Chrome  Orange   191 

Tests  for  Bichromate  of  Potash   193 

Vanadium   193 

tungstenum,  or  wolfram                                               .      .  194 

Molybdenum   195 

Peroxide  of  Molybdenum    .      .       .       .       .      .       .      .  195 

Molybdic  Acid   195 

Tellurium   196 

Tellurous  Acid   196 

Telluric  Acid   196 

Arsenic   196 

Arsenious  Acid   197 

Arsenic  Acid   198 

Sulphurets  of  Arsenic   198 

Antimony   199 

Oxide  of  Antimony   199 

Sulphate  of  Antimony   199 

Antimonious  Acid   200 

Antimonic  Acid   200 

Uranium   200 

Protoxide  of  Uranium   200 

Peroxide  of  Uranium   201 

Cerium   201 

Mercury   202 

Suboxide  of  Mercury  .       .       .       .             .       .       .       .  202 

Protoxide  of  Mercury — Peroxide  of  Mercury    ....  202 

Silver   203 

Nitrate  of  Silver   .204 

Sulphate  of  Silver   204 


xiv 


CONTENTS. 


PAGE 

Gold   205 

Subch'loride  of  Gold   206 

Perehloride  of  Gold   206 

Platinum  '.              ...  206 

Palladium  ,   207 

Iridium)   208 

Osmium      .      .      ...       .       ....       .       .  209 

Khodium   209 

Lanthanium                                                                           .  210 

TEXTILE  FIBRES. 

Cotton   211 

Flax  .       .      .       .      .  '     .       .      .       ...       .  .211 

Hemp   212 

Silk    .      .      ,   212 

Wool   .       .  .212 

Generalities  on  Textile  Fibres   213 

MORDANTS. 

Red  Spirits       .       .       .       .      .       .       .       .       .       .     '  .  224 

Barwood  Spirits                                                         .       .       .  225 

Plum  Spirits   .  .226 

Yellow  Spirits   226 

Nitrate  of  Iron  .       .       .       .       .       ....       .       .       .  227 

Acetate  of  Iron  and  Alumina                                              .       .  227 

Acetate  of  Alumina   .       .       .       .       .       .              .       .       .  227 

Black  Iron  Liquor     .       .       .   227 

Iron  and  Tin  for  Royal  Blue      .       .       .     ...       .       .       .  .227 

Acetate  of  Copper   228 

VEGETABLE  MATTERS  USED  IN  DYEING. 

Introductory  Remarks                                                   .       .  234 

Galls    241 

Sumach      .      .   249 

Catechu                                                                  ...  254 

Valonia  Nuts   258 

Divi  Divi   258 

Myrobalans   258 

INDIGO. 

Manufacture  of  Indigo   261 

Testing  of  Indigo   266 

Commercial  Indigoes   274 

Characteristics  of  Indigo    .   276 

Indigo  Dyeing    ....    281 


CONTENTS. 


XV 


PAGE 

Sulpho-purpuric  Acid   283 

Sulphate  of  Indigo   285 

Indigo  Extract   285 

The  Blue  Yat   287 

Woad  and  Pastel  -  .  292 

Indigo  Blue       .    292 

Pastel  Yat   .       .  .294 

Woad  Yat   297 

Modified  Pastel  Yat   298 

Indian  Yat   .  .299 

PqtashYat   300 

German  Yat                                                             ...  300 

Management  of  the  Vats   302 

Logwood   306 

Brazil  Woods  .       .       .       .       .             ..      .       ."      .       .  314 

Santal  or  Sandal  Wood   317 

Barwood   317 

Camwood   320 

Fustic  or  Yellow  Wood   321 

Young  Fustic   322 

Bark  or  Quercitron        .       .   323 

Flavine     .   325 

Extracts  of  Woods   326 

Weld  or  Wold   326 

Turmeric   328 

Persian  Brrries   328 

Safflower  or  Carthamus        .   329 

Madder   333 

Levant  Madder   334 

Dutch  Madder   334 

Alsace  Madder    .       .       .   335 

Madder  of  Avignon     .       .   335 

Madder  Purple    .   338 

Madder  Ked   338 

Madder  Orange   339 

Madder  Yellow    .       .       .       .       .       .       .    ■  .       .       .  339 

Madder  Brown    .       .       .       .......  339 

Madder  Acids   339 

Useful  Products                                                                .  339 

Madder  Preparations   340 

Chlorine   343 

Coloring  Principles  of  Madder   344 

Tests  for  Madder   346 

Munjeet     .       .       .   348 

Annotta  or  Arnotto   348 

Alkanet  Root                                                                       .  352 

Archil   352 


xvi  CONTENTS. 


PEOPOSED  NEW  VEGETABLE  DYES. 

PAGE 

SoORANJEE   355 

Carajuru  or  Chica   358 

Wongshy   359 

Aloes   363 

PlTTACAL   364 

Barbary  Koot   364 

ANIMAL  MATTERS  USED  IN  DYEING. 

Cochineal   365 

Carmine   366 

Lake  Lake  or  Lac    .       .       .   370 

Kerms  or  Kermes   .371 

MUREXIDE   371 

COLORS  DERIVED  FROM  COAL  TAR. 

Production  of  Coal  Tar   373 

Composition  of  Coal  Tar   373 

Distillation  of  Coal  Tar     .   374 

Aniline   375 

Theory  of  Aniline  Colors   377 

Aniline  Reds  \       .  .380 

Aniline  Blues  and  Yiolets   381 

Aniline  Yellows   382 

Aniline  Greens   383 

Aniline  Blacks  and  Grays   384 

Aniline  Browns  and  Maroons   .       .  385 

Colors  derived  from  Carbolic  or  Phenic  Acid      ....  385 

Colors  derived  from  Naphthaline   387 

Remarks  in  General  on  Coal  Tar  Colors   388 

Remarks  in  General  on  Dyeing  with  Coal  Tar  Colors  .  .  .  389 
Determination  of  the  Coloring  Power  and  Nature  of  Aniline 

Colors   391 

Identification  of  Aniline  Colors  .      ...       .       .       .  392 


APPENDIX. 

Dyeing  and  Calico  Printing  as  shown  in  the  Universal  Exposition, 
Paris,  1867 

Extracts  from  the  Reports  of  the  International  Jury,  and  from  other 


Sources   395 

Glossary  of  Technical  Terms  used  in  the  Dye-House  with  the 

Chemical  Names   399 

Index   403 


A  SYSTEM 


OF 

CHEMISTRY  APPLIED  TO  DYEING. 


GENERAL  PROPERTIES  OF  MATTER. 


HEAT. 

Conditions  of  Matter. — Matter,  which  is  everything  ca- 
pable of  affecting  the  senses,  exists  in  three  different  states — 
solid,  fluid,  and  gaseous.  Looking  upon  matter  in  any  of  these 
states,  the  most  casual  observer  cannot  fail  to  distinguish  a 
great  variety  of  appearance.  For  example — stone  differs  from 
brick,  bread  from  wood,  and  iron  from  both,  among  the  solid 
forms;  while  differences  quite  as  great  are  seen  both  in  fluids 
and  amongst  gases.  But,  although  these  differences  are  familiar 
to  all,  there  are  few  who  inquire  the  cause  why,  under  the  same 
circumstances,  one  portion  of  matter  exists  as  a  solid,  another 
as  a  fluid,  and  a  third  as  a  gas.  Correct  answers  to  these  in- 
quiries are  the  objects  of  all  scientific  research.  They  are,  in 
their  nature  twofold — physical  and  chemical.  The  former,  em- 
bracing the  study  of  matter  in  mass,  takes  cognizance  of  shape, 
measure,  hardness,  weight,  flexibility,  tenacity,  divisibility,  and 
such  like  properties;  while  the  latter,  the  chemical,  investigates 
those  more  remote  differences  which  depend  on  the  relative 
powers,  properties,  and  mutual  actions  of  the  elemental  com- 
ponents of  the  given  substance — an  inquiry  which  embraces  a 
universal  interrogation  of  all  kinds  of  matter. 

Heat  the  Cause  of  Conditions  of  Matter. — That  one 
body  is  solid,  another  fluid,  and  a  third  gaseous,  is  an  inquiry 
which  belongs  more  directly  to  physics  than  to  chemistry ;  yet 
heat,  which  is  the  cause  of  these  differences,  is  so  intimately 
connected  both  with  the  molecular  changes,  and  the  constitution 
of  bodies,  particularly  of  the  coloring  matters  used  in  dyeing, 
that  it  will  be  proper  to  enumerate,  preliminarily,  a  few  of  its 
most  prominent  effects  and  general  laws,  for  convenience  of 
2 


18 


HEAT  THE  CAUSE  OF  CONDITIONS  OF  MATTER. 


frequent  reference  when  we  come  to  speak  of  the  practical  effects 
of  those  laws  on  many  of  the  operations  in  the  dye-house. 

All  bodies  are' supposed  capable  of  existing  in  the  three  states 
— solid,  fluid,  and  gaseous — by  the  addition  or  subtraction  of 
heat ;  but  the  same  degree  of  heat  does  not  affect  all  kinds  of 
bodies  to  the  same  extent.  For  example — water,  subject  to 
the  ordinary  pressure  of  the  atmosphere,  at  32°  Fah.  and  under, 
is  solid;  from  32°  to  212°  it  is  fluid;  and  from  212°  upwards  it 
is  gaseous;  while  quicksilver,  another  fluid,  at  ordinary  tem- 
perature, does  not  become  solid  until  it  is  cooled  72°  below  that 
of  the  solidifying  point  of  water,  and  does  not  pass  into  the 
gaseous  state  until  it  is  heated  upwards  of  400°  above  the 
aeriform  point  of  water.  Again,  lead  and  several  other  bodies 
only  become  fluid  at  the  temperature  which  gassifies  quicksilver. 
The  following  table  will  make  this  more  apparent: — 


Solid 

Becomes 

Becomes 

Range  of 

matter 

fluid  at 

gaseous  at 

fluidity. 

Sulphurous  Acid  about 

—105 

about  — 105 

+12  to  +14 

118 

'  +  32  and  a  pres- 

Carbonic Acid  about 

—112- 

sure  of  36  atmo- 

| -71(0 

spheres 

Mercury 

—  39 

—  39 

+662 

701 

Water. 

+  32 

+  32 

+212 

180 

Tin  ... 

442 

442 

about  2400 

about  1958 

Lead  .... 

626 

626 

Not  known 

Bismuth 

480 

480 

a  u 

Arsenic 

356 

Under  pressure 

Dark  red  heat 

Silver  .       .  ... 

2283 

2283 

Not  known 

Cast-Iron 

3479 

3479 

ft  it 

This  table  shows  how  differently  the  same  degree  of  heat 
affects  different  substances.  W4  cannot  conceive  a  condition 
so  cold  that  all  matter  would  be  solid,  nor  so  hot  that  all  would 
be  gaseous.  In  the  cases  of  carbonic  acid  and  arsenic,  there 
appears  an  exception:  these  bodies  have  no  fluid  range — 
they  have  no  existence  in  a  fluid  state.  They  may  be  ob- 
tained fluid  by  pressure;  but  this  is  under  extraordinary  cir- 
cumstances, and  the  particles  still  retain  their  elasticity,  which 
a  true  fluid  does  not.  But  when  in  the  solid  state,  and  under 
ordinary  conditions — that  is,  under  the  ordinary  pressure  of  the 
atmosphere — it  passes  directly  from  the  solid  to  the  gaseous  state. 

Some  philosophers,  reasoning  from  analogy,  and  not  admit- 
ting any  exceptions  to  general  laws  in  nature,  object  to  the 
apparent  fact,  and  give,  as  their  opinion,  that  such  substances 
as  carbonic  acid  really  have  a  fluid  range,  but  being  so  little, 
probably  only  a  few  degrees,  the  body  may  pass  through  that 
state  without  observation.  This  supposition  is  untenable,  and 
is  founded  upon  a  mistaken  view  of  what  is  a  general  law. 
The  range  of  fluidity  of  any  body  depends  upon  the  amount 


MEASURES  OF  TEMPERATURE. 


19 


of  pressure  which  the  body  is  subject  to.  There  are  many 
other  bodies,  besides  carbonic  acid  and  arsenic,  that  require  a 
greater  amount  of  pressure  than  that  of  our  atmosphere  to 
maintain  them  in  the  fluid  state;  so  that  both  the  facts  and 
the  circumstances  are  quite  in  accordance  with  the  general 
laws  of  nature. 

General  Effects  of  Heat. — In  connection  with  the  ge- 
neral laws  of  heat,  we  may  notice,  first,  that  bodies  when  they 
become  heated  expand,  or  become  larger — the  particles  which 
compose  them  seem  to  separate  farther  from  one  another. 
This  effect  is  produced  upon  matter  in  all  states.  Familiar 
illustrations  of  this  effect  of  heat  are  numerous.  If  a  pair  of 
tongs,  with  legs  of  equal  length,  have  one  of  the  legs  put  into 
the  fire  and  made  red  hot,  it  will  be  found,  in  this  state,  longer 
than  the  other.  It  is  well  known  to  dyers,  that  if  a  boiler 
be  filled  to  within  a  little  of  the  mouth  with  cold  water,  and 
a  fire  put  under  it,  by  the  time  it  begins  to  boil  the  water  runs 
over,  having  enlarged  so  much  that  the  boiler  is  too  small  to 
contain  it  when  hot.  And  another  circumstance  often  occurs — 
when  a  certain  quantity  of  a  decoction  of  a  dye  is  required, 
and  is  measured  out  of  the  boiler  in  gross  while  hot,  and  then 
distributed  in  its  required  proportions  when  cold,  there  is  often 
wanting  a  considerable  portion  of  liquid,  causing  serious  annoy- 
ances in  the  dye-house,  when  the  difference  of  temperature  is 
not  taken  into  consideration. 

That  gaseous  bodies  are  affected  in  the  same  way  by  heat, 
may  be  illustrated  by  taking  a  bladder,  and  filling  it  three 
parts  full  with  cold  air,  tying  it  round  the  neck,  and  holding 
it  before  a  fire — or,  what  is  better,  taking  the  bladder  into  the 
drying-stove  connected  with  the  dye-house.  In  a  very  little 
time  the  bladder  becomes  distended  and  quite  full,  and  may 
be  made  to  burst  by  the  expansion  of  the  air,  if  the  heat  be 
high,  or  the  bladder  nearly  filled. 

Measures  of  Temperature. — Upon  this  expansive  effect 
of  heat  is  founded  the  means  of  measuring  its  intensity.  Our 
senses  tell  us  when  a  body  is  hot  or  cold,  but  they  are  very 
imperfect  indicators  of  the  degree  or  intensity  of  the  heat. 
Our  own  temperature  being  the  standard,  we  can  only  tell 
that  a  substance  is  hotter  or  colder  than  our  own  body.  In 
the  dye-house,  where  the  hand  is  often  made  the  indicator  of  the 
temperature  of  the  dyeing  liquid,  the  result  varies  according  to 
whether  the  person  has  been  previously  working  in  hot  or  cold 
liquids,  and  is  therefore  a  very  imperfect  test  of  temperature, 
and  often  productive  of  evils  by  giving  different  tints  of  shades, 
and  deteriorating  the  beauty  of  a  color.  Temperature  is  very 
correctly  measured  by  observing  the  amount  of  expansion  in 


20 


COMPARATIVE  VALUE  OF  THE  SCALES. 


any  given  body.  Instruments  for  this  purpose  are  plentiful 
and  cheap;  we  will  therefore  not  require  to  detail' their  mode 
of  manufacture,  but  a  good  thermometer  is  an  essential  instru- 
ment in  the  dye-house,  and  ought  to  be  constantly  employed. 
The  thermometers  used  in  this  country  are  generally  those  of 
Fahrenheit.  The  scale  of  measurement  of  this  has  been  deter- 
mined in  the  following  manner:  Fahrenheit  divided  the  two 
points,  from  the  freezing  of  water  to  its  boiling,  into  180  deg- 
rees ;  he  called  the  freezing  point  the  32d  degree,  from  some 
reason  of  his  own;  hence  32°  +  180°  =  212,  the  boiling  point 
of  water,  according  to  Fahrenheit.  There  is  another  scale 
sometimes  used,  called  Reaumur's.  This  has  the  two  points,  from 
the  freezing  to  the  boiling  of  water,  divided  into  80  degrees. 
Another,  and  more  generally  used  scale,  has  the  range  from 
freezing  point  to  boiling  of  water  divided  into  100° ;  thus  the 
freezing  point  is  marked  0,  the  boiling  point  100.  This  is 
termed  the  Centigrade  thermometer.  In  reading  books  where 
temperature  is  referred  to — such  as  in  many  dyeing  recipes 
and  processes — attention  must  be  paid  which  thermometer 
scale  is  referred  to.  They  are  generally  indicated  by  abbrevia- 
tions— as  F.,  or  Fah.,  for  Fahrenheit's  scale,  R.,  or  Reau.,  for 
Reaumur's,  and  C.  for  the  Centigrade.  The  following  table  of 
the  comparative  value  of  the  different  scales,  will  guide  the 
operator  in  using  one  or  other  of  them : — 


Gent. 

Fah. 

Cent. 

Fah. 

Cent. 

Fah. 

0    .  . 

.  32 

21  .  . 

.  69.8 

42  .  . 

.  107.6 

1  . 

.  33.8 

22  .  . 

.  71.6 

43  .  . 

.  109.4 

2  . 

.  35.6 

23  .  . 

.  73.4 

44  .  . 

.  111.2 

3  . 

.  37.4 

24  . 

.  75.2 

45  .  . 

.  113 

4  . 

.    .  39.2 

25  .  . 

.  77 

46  .  . 

.  114.8 

5  . 

.  41 

26  .  . 

.  78.8 

47  .  . 

.  116.6 

6  . 

.  42.8 

27.  . 

.  80.6 

48  .  . 

.  118.4 

7  . 

.    .  44.6 

28  .  . 

.  82.4 

49  .  . 

.  120.2 

8  . 

.    .  46.4 

29  .  . 

.  84.2 

50.  . 

.  122 

9  . 

.    .  4«.2 

30.  . 

.  86 

51  .  . 

.  123.8 

10  . 

.    .  50 

31  .  . 

.  87.8 

52  ..  . 

.  125.6 

11  . 

.    .  51.8 

32  .  . 

.  89.6 

53  .  . 

.  127.4 

12  . 

.    .  53.6 

33  .  . 

.  91.4 

54  .  . 

.  129.2 

13  . 

.    .  55.4 

34  .  . 

.  93.2 

55  .  . 

.  131 

14  . 

.    .  57.2 

35  .  . 

.  95 

56  .  . 

.  132.8 

15  . 

.    .  59 

36  .  . 

.  96.8 

57  .  . 

.  134.6 

16  . 

.    .  60.8 

37  .  . 

.  98.6 

58  .  . 

.  136.4 

17  . 

.    .  62.6 

38  .  . 

.  100.4 

59  .  . 

.  138.2 

18  . 

.    .  64.4 

39  .  . 

.  102.2 

60  .  . 

.  140 

19  . 

.    .  66.2 

40  .  . 

.  104 

61  .  . 

.  141.8 

20  . 

.    .  68 

41  .  . 

.  105.8 

62  .  . 

.  143.6 

SUBSTANCES  AFFECTING  BOILING  POINT.  21 


Cent. 

Fah. 

Cent. 

Fah. 

Cent. 

Fah. 

63  .  . 

.  145.4 

76  .  . 

.  168.8 

89  .  . 

.  192.2 

64  .  . 

.  147.2 

77  .  . 

.  170.6 

90  .  . 

.  194 

65  .  . 

.  149 

78  .  . 

.  172.4 

91  .  . 

.  195.8 

66  .  . 

.  150.8 

79  .  . 

.  174.2 

92  .  . 

.  197.6 

67  .  . 

.  152.6 

80  .  . 

.  176 

93  .  . 

.  199.4 

68  .  . 

.  154.4 

81  . 

.  177.8 

94  .  . 

.  201.2 

69  .  . 

.  156.2 

82  . 

.  179.6 

95  .  . 

.  203 

70  .  . 

.  158 

83  .  . 

.  181.4 

96  .  . 

.  204.8 

71  .  . 

.  159.8 

84  . 

.  183.2 

97.  . 

.  206.6 

72  .  . 

.  161.6 

85  .  . 

.  185 

98  .  . 

.  208.4 

73  .  . 

.  163.4 

86  .  . 

.  186.8 

99  . 

.  210.2 

74  .  . 

.  165.2 

87  . 

.  188.6 

100  . 

.  212 

75.  . 

.  167 

88  . 

.  190.4 

It  will  be  seen  from  this  table  that  every  5  degrees  of  the 
Centigrade  scale  is  equal  to  9  Farenheit ;  so  that  any  degree  of 
the  one  may  be  converted  into  the  other  by  a  simple  rule, 
namely,  by  multiplying  the  Centigrade  by  9,  and  dividing  by 
5,  then  adding  32°.  Thus,  if  any  liquid  is  recommended  to  be 
at  60°  C,  then  60°  Cent,  x  9  ~  5  +  32°  =  140°  F. ;  or  by 
Reaumur's,  the  only  difference  in  the  process  is  to  divide  by  4 
instead  of  by  5.    Thus,  60°  R,  x  9-4  +  32°  =  167°  F. 

Boiling  of  Liquids. — The  heating  and  boiling  of  liquids  is 
explainable  by  the  principle  of  expansion.  When  heat  is 
applied  to  a  vessel  holding  water,  the  particles  of  water  nearest 
the  fire  become  heated,  and  consequently  expand  ;  and,  in  this 
expanded  state,  being  lighter  than  the  particles  above  them, 
they  rise  to  the  surface,  and  give  place  to  another  layer  of  par- 
ticles. These  particles  are  in  turn  heated,  and  rise  to  the  sur- 
face ;  and  so  on,  successively,  until  the  fluid  is  all  heated  to  the 
point  at  which  it  passes  off  as  vapor  or  steam.  The  exact 
temperature  at  which  this  takes  place  is  stated  above  as  212° 
Fah.,  but  varies  a  little  from  the  amount  of  pressure  upon  its 
surface,  so  that  water  boils  at  a  lower  heat  upon  a  high  hill 
than  at  the  foot  of  it ;  and,  for  the  same  reason,  it  requires  a 
higher  temperature  to  boil  the  water  at  the  bottom  of  a  deep 
pit  than  upon  the  surface  at  the  mouth  of  the  pit,  there  being 
a  greater  pressure  of  air  at  the  bottom  of  the  pit  in  proportion 
to  the  depth. 

Substances  affecting  Boiling  Point. — Anything  that 
gives  an  increased  attraction  to  the  particles  of  a  fluid  also 
raises  the  temperature  of  the  boiling  point.  Some  kinds  of  ves- 
sels, such  as  glass  and  polished  metals,  retain  the  water  with 
greater  force  than  rough  vessels,  hence  it  requires  a  little 
higher  heat  to  boil  water  in  vessels  of  polished  material. 


22 


STRONG  BOILING. 


Water,  upon  the  surface  of  oil,  boils  two  degrees  of  heat  below 
water  in  a  glass  vessel,  in  consequence  of  the  oil  having  no 
attraction  for  water. 

Substances  dissolved  in  water  have  often  a  similar  effect,  the 
attraction  of  the  two  substances  having  to  be  overcome.  Thus, 
alkaline  lyes — soda  or  potash  dissolved  in  water — require  higher 
temperatures  to  boil  them  than  pure  water  does.  But,  connected 
with  this,  we  may  mention  a  circumstance  of  great  importance 
in  the  dye  house.  In  boiling  alkaline  lyes,  so  strong  is  the 
attraction  of  the  water  for  the  alkali,  that  it  carries  a  small 
quantity  with  it  in  passing  off*  as  steam ;  so  that  great  care 
should  be  taken  in  a  dye-house  where  lyes  are  being  boiled, 
that  the  steam  or  vapor  does  not  come  into  contact  with  any 
colors  that  will  be  affected  by  alkalies.  Whei:e  convenient, 
it  is,  indeed,  safest  to  have  all  alkaline  lyes  boiled  entirely 
apart  from  wrhere  any  colored  goods  are  likely  to  be  exposed 
to  the  influence  of  these  vapors.  We  have  seen  many  annoying 
and  expensive  accidents  caused  by  neglecting  this  precaution, 
especially  upon  such  colors  as  safflower  reds,  and  Prussian 
blues. 

Strong  Boiling. — Another  circumstance  of  common  occur- 
rence in  the  dye-house  is  what  is  termed  strong  boiling.  This 
means  that,  in  the  process  of  boiling,  we  increase  the  fire,  in 
order  to  give  the  liquor  more  heat,  and  make  it  hotter.  We 
need  hardly  say  that  this  is  an  error;  for  a  liquid  at  the  boil- 
ing point  cannot  be  more  heated  by  increase  of  fire.  All  that 
is  required  is  as  much  heat  as  will  retain  it  on  the  spring  of 
the  boil,  and  the  liquid  will  then  be  as  hot  as  though  it  boiled 
with  the  greatest  violence.  The  only  difference  in  strong 
boiling  is,  that  much  more  steam  is  driven  off,  which  carries 
off  the  heat  applied,  and  lessens  the  quantity  of  solution  ;  still, 
if  a  thermometer  be  placed  in  the  liquor,  the  temperature  is 
found  to  be  the  same,  and  the  only  effect  is  that  the  heat  is 
more  rapidly  carried  off  by  the  steam,  and  lost.  The  amount 
of  heat  which  steam  thus  imbibes  and  takes  away,  is  calculated 
in  round  numbers,  at  1000°  Fah.,  which  may  be  illustrated  as 
follows  :  If  one  pound  of  water,  at  32°,  requires  the  burning  of 
a'  pound  of  coal  to  bring  it  to  the  boiling  point  (212°),  the 
water  will  have  received  180°  of  heat;  if  the  fire  be  continued 
at  the  same  rate,  it  will  take  5 J  lbs.  of  coal  to  convert  the 
pound  of  boiling  water  into  steam,  and  the  temperature  of  the 
steam  will  never  be  above  212°  Fah.;  thus  1000°  of  heat  have 
been  taken  up  by  the  steam,  and  retained  in  a  latent  state — 
that  is  to  say,  in  a  state  not  sensible  to  the  thermometer.  Or 
we  may  illustrate  this  principle  by  another  experiment:  if  we 
take  5  J  lbs.  of  water  at  32°,  and  pass  a  jet  of  steam  at  212° 


CHEMICAL  EFFECTS  OF  HEAT  UPON  COLORS. 


23 


through  it,  until  the  water  begins  to  boil,  the  whole  water  will 
weigh  lbs.;  thus  1  lb.  of  steam  has  brought  5|  lbs.  of  water 
up  180°,  thereby  showing  that  this  pound  of  steam  had  con- 
tained 1000°  of  heat.  These  facts  the  practical  dyer  can  easily 
apply  to  his  own  purposes.  Steam  is  very  generally  used  in 
the  dye-house  as  a  heating  agent  for  water,  making  decoctions, 
and  the  boiling  of  goods.  It  is  an  observed  fact  that  steam  is 
not  so  effective  for  many  purposes  as  fire — as  in  the  making  of 
some  decoctions.  In  the  using  of  steam  for  boiling,  some  of 
the  circumstances  referred  to  ought  to  be  kept  in  mind,  such  as 
the  fact  that  steam  cannot  raise  the  temperature  of 'the  boiling 
liquid  above  212°.  Hence  the  conditions  noticed  of  the  raising 
the  boiling  point  of  water  by  the  presence  of  matters  held  in 
solution,  and  by  different  kinds  of  vessels,  do  not  apply  to 
liquids  when  boiled  by  steam.  This  may  be  one  cause  of  the 
observed  difference  of  effect  in  the  dye-house.  Again,  water 
boiled  by  passing  a  jet  of  ordinary  pressure  steam  into  it,  never 
gets  above  210°,  a  small  deficiency,  but  sufficient  to  cause  a 
difference  in  the  results  of  many  operations  in  the  workshop. 

This  fact  may  be  accounted  for  by  the  circumstance  that  in 
this  process  there  is  no  attraction  of  the  water  by  the  surface 
of  the  vessel,  as  when  boiled  by  fire,  which,  as  has  been  ob- 
served by  Berzelius,  causes  the  boiling  point  in  different  vessels 
to  vary  upwards  of  2°.  In  boiling  by  steam,  no  such  attraction 
has  to  be  overcome  as  that  between  the  vessel  and  water ; 
hence  the  boiling  point  is  lower,  and  210°  may  be  actually  the 
true  boiling  point  of  water.  For  all  ordinary  purposes, 
however,  steam,  as  a  heating  agent,  is  of  the  highest  value  to 
the  dyer. 

Chemical  Effects  of  Heat  upon"  Colors. — The  effects  of 
heat  in  relation  to  chemical  combination  and  decomposition, 
are  of  the  utmost  importance  in  all  the  operations  of  the  dyer. 
The  influence  of  heat  in  producing  particular  tints  and  colors, 
and  also  upon  many  colors  when  produced,  are  subjects  of 
every-day  observation.  Nevertheless,  the  consequences  are 
often  so  important,  that  the  subject  cannot  be  too  fully  im- 
pressed upon  the  minds  of  all  interested.  We  shall,  therefore, 
enumerate  a  few  of  the  more  prominent  effects  in  this  place. 

In  making  a  decoction  of  quercitron  bark,  for  dyeing  yellow, 
if  it  is  made  at  a  temperature  of  about  90°,  a  much  finer  and 
purer  yellow  is  obtained  than  when  the  decoction  is  made  by 
boiling.  When  woollen  cloth  is  dyed  by  bark,  and  then  hot- 
pressed,  the  heat  impairs  the  color ;  but  generally  dyed  colors 
are  more  liable  to  be  affected  by  heat  when  moisture  is  present, 
than  in  a  dry  atmosphere.  For  instance — a  safflower  red  will 
stand  a  high  temperature  when  the  air  is  dry,  but  if  moisture  be 


24 


CHEMICAL  EFFECTS  OF  HEAT  UPON  COLOKS. 


present,  it  passes  rapidly  into  a  yellowish  brown.  If  a  Prussian 
blue  be  placed  in  a  moist  atmosphere,  and  raised  to  the  tempera- 
ture of  about  300°  Fah.,  it  fades  entirely  in  a  few  hours.  Many 
of  the  coloring  matters  of  flowers,  when  imparted  to  cloth;  may 
be  dried  without  change  in  the  cold  and  dark,  and  afterwards 
be  submitted  to  a  temperature  of  200°  without  alteration,  but 
could  not  stand  a  temperature  of  95°  without  being  altered 
were  these  precautions  not  taken  ;  such  colors,  therefore,  if  put 
on  goods,  could  not  be  dried  in  a  stove. 

The  kind  of  material  on  which  the  color  is  dyed  also  influ- 
ences the  effects  of  heat.  Indigo  blue  dyed  upon  cotton  is 
permanent,  exposed  to  heat  and  moisture ;  but  the  same  color, 
with  the  same  dyestuff,  upon  silk,  is  readily  changed  under 
those  conditions.  Safflower  colors  upon  silk  and  cotton,  placed 
under  similar  circumstances  in  regard  to  heat  and  moisture, 
are  affected  oppositely  ;  that  on  the  cotton  is  completely  de- 
stroyed before  that  upon  the  silk  is  at  all  affected. 

Thus  we  find  that  heat  operates  upon  colors  differently  when 
the  heated  atmosphere  or  color  is  dry  and  when  it  is  moist, 
which  suggests  the  propriety  of  paying  strict  attention  to  the 
condition  of  the  drying-stove,  and  the  hanging  of  the  colored 
fabrics,  so  as  to  give  a  free  outlet  to  all  moisture.  If  this  is 
neglected,  the  colors  are  subjected  to  a  hot  vapor-bath,  and  are 
under  the  most  favorable  conditions  to  be  destroyed  by  the 
joint  action  of  the  heat  and  steam. 

The  same  kind  of  coloring  matter  fixed  upon  cotton  by  dif- 
ferent mordants,  is  affected  by  heat  differently,  whether  mois- 
ture be  present  or  not.  This  can  be  observed  daily  of  logwood 
colors,  when  fixed  by  tin  or  by  alumina.  The  different 
changes  which  these  colors  undergo  in  the  process  of  drying, 
and  the  dependence  of  these  upon  the  state  of  the  stove,  as  to 
being  hot  and  dry  or  hot  and  moist,  are  familiar  to  the  practical 
dyer.  But  as  we  shall  have  occasion  to  notice  some  of  these 
changes  when  describing  the  dyestufts,  and  the  colors  produced, 
we  pass  over  the  details  in  this  place.  The  following,  how- 
ever, may  be  stated  as  a  general  rule,  namely — that  all  organic 
coloring  matters  are  destroyed  at  a  red  heat.  There  are  some, 
however,  such  as  indigo,  which  sublime,  or  may  be  distilled 
by  a  heat  less  than  sufficient  to  effect  their  destruction. 
Those  coloring  matters  which  are  volatile  are  in  general  most 
permanent  when  fixed  upon  fabrics,  and  resist  the  action  of 
heat  best;  and  those  colors  that  do  not  sublime  are  most  sus- 
ceptible of  decomposition  under  the  combined  influence  of  air, 
heat,  and  moisture. 


25 


LIGHT. 

Nature  of  Light. — The  effects  of  light  upon  colors  are  so 
closely  related  to  that  of  heat,  and  so  powerful — particularly 
the  direct  rays  of  the  sun — that  we  cannot  pass  over  the  con- 
sideration of  those  accidental  phenomena,  which  we  must  un- 
derstand as  independent  altogether  of  that  essential  relation 
which  light  has  to  produce  color.  Strictly  speaking,  colors 
have  no  material  existence,  but  are  altogether  the  effect  of 
light — at  least,  colors  do  not  exist  in  the  objects  appearing 
colored,  but  in  the  light  which  is  reflected  from  the  apparently 
colored  object.  In  order,  then,  to  define  color,  we  may  briefly 
state  what  is  known  upon  the  nature  and  composition  of  light 
— at  least,  so  far  as  is  necessary  for  our  present  purpose. 

A  beam  of  light  is  composed  of  three  differently  colored 
rays — red,  blue,  and  yellow — termed  sometimes  the  luminous, 
calorific,  and  chemical  rays,  from  their  different  properties  of 
giving  out  heat  and  light,  or  in  exciting  chemical  action. 
When  a  beam  of  light  strikes  the  surface  of  a  body,  it  bounds 
off  as  an  elastic  ball  would  do  striking  the  same  surface,  and 
this  bounding  off  is  termed  reflection  ;  or,  it  is  absorbed  by 
the  body  and  disappears,  and  is  altogether  extinguished;  or, 
lastly,  it  passes  through  the  body,  making  it  transparent.  In 
the  first  case,  the  bounding  or  reflected  rays  pass  into  the  eye, 
and  the  body  from  which  it  is  reflected  appears  white  or  some 
particular  color.  In  the  second  place,  there  can  no  light  pro- 
ceed from  the  object  to  the  eye,  it  being  absorbed  and  ex- 
tinguished— the  body,  therefore,  is  invisible ;  or,  if  the  sur- 
rounding objects  are  illuminated,  or  reflect  light,  it  appears 
black ;  and,  in  the  third  place,  the  light  passing  through  un- 
altered, the  body  appears  clear.  The  less  the  light  is  altered, 
the  more  clear  and  transparent  the  body,  and  consequently 
the  more  nearly  invisible.  Thus,  that  which  we  are  accus- 
tomed to  call  white  light  is  the  simultaneous  transmission  of 
three  colored  rays.  Thus  also,  when  light  is  admitted  into 
a  dark  room  through  a  small  aperture — say  a  hole  in  a  window- 
shutter — and  a  glass  prism  is  placed  in  the  aperture,  so  that 
the  light  passes  through  it  and  is  made  to  fall  upon  a  sheet  of 
white  paper,  the  light  is  decomposed,  and  appears  upon  the 
paper  in  the  following  order  of  colors:  — 


26 


RELATION  OF  COLORS  TO  THE  FABRIC. 


Violet.    »  Green.  Orange. 

Indigo.  *Yellow.  *Ked. 

*Blue. 

These  are  termed  the  seven  prismatic  colors,  and  the  share 
they  all  occupy  is  termed  the  spectrum,  of  which  each  occu- 
pies a  definite  breadth.  Those  marked  by  a  *  are  the  only 
simple  colors — that  is,  requiring  no  admixture — the  others  are 
produced  by  a  mixture  of  different  colors,  and  are  therefore 
compound.  The  violet  and  indigo,  for  example,  are  composed 
of  a  mixture  of  blue  and  red;  the  green  is  a  mixture  of  blue 
and  yellow,  and  the  orange  of  yellow  and  red.  Hence  the 
primary  colors  are  blue,  red,  and  yellow.  The  equal  admixture 
of  these  three  colors  gives  white  light ;  but  anything  disturbing 
that  simultaneous  equality,  produces  a  color  according  to  the 
nature  and  amount  of  disturbance.  Thus,  the  prism  through 
which  the  light  entered  the  room,  in  the  experiment  referred 
to,  from  its  shape  and  properties  effects  a  complete  disturbance, 
and  the  different  colors  are  made  visible.  Similar  effects  are 
produced,  as  has  been  already  stated,  when  the  light  is  reflected 
from  a  surface.  If  the  different  colored  rays  are  not  reflected 
or  absorbed  in  the  same  ratio,  the  result  is  a  color  according  to 
the  difference  in  the  reflection  or  absorption  of  the  different  ray 
or  rays.  If  the  red  ray  is  absorbed,  and  only  the  blue  and 
yellow  rays  reflected,  the  object  from  which  they  are  reflected 
appears  green  ;  if  the  yellow  ray  is  also  absorbed,  the  object 
appears  blue ;  or  if  it  has  been  the  blue  ray  that  is  absorbed, 
and  red  and  yellow  reflected,  the  object  appears  orange ;  or  if 
the  yellow  ray  only  is  absorbed,  the  object  appears  violet  or 
purple.  Thus,  by  the  rate  of  the  disturbing  influence,  and  the 
different  combinations  of  these  three  colors,  are  all  the  various 
shades  in  nature  produced. 

Relation  of  Colors  to  the  Fabric— Although  these  re- 
marks go  to  prove  that  color  has  no  material  existence  in  the 
body  appearing  colored,  still  the  question  is  one  of  chemical 
science.  As  every  chemical  change  affects  the  character  of  the 
substance  in  its  relations  to  light,  the  dyer's  object  is  to  effect 
a  combination  with  his  stuffs  that  will  produce  certain  effects 
upon  light,  and  thereby  produce  colors.  It  is  found,  sometimes, 
that  the  nature  of  the  fabric  affects  the  beauty  and  tint  of  a 
color.  A  chemical  compound  alone  may  be  obtained  that  vies 
with  nature,  both  in  the  beauty  and  brilliancy  of  its  color; 
but,  when  that  is  obtained  within  the  fibre  of  silk,  cotton,  or 
wool,  the  light  must  be  transmitted  through  the  material  as  a 
medium,  and  the  fibre  not  being  transparent,  the  original  beauty 
of  the  color  is  much  diminished.    Hence  the  same  color,  fixed 


EFFECTS  OF  DIFFERENT  RAYS  UPON  COLORS. 


27 


within  the  fibres  of  those  three  substances,  has  different  ap- 
pearances in  each ;  the  cotton  never  yields  the  beauty  of  color 
that  the  silk  does,  or  even  the  wool.  These  circumstances,  in 
all  their  relations,  afford  matter  of  constant  study  to  the  prac- 
tical dyer. 

It  may  be  said  that  we  cannot  follow  nature  in  the  production 
of  colors — that  were  the  dyer  to  attempt  to  produce  a  white  by 
an  exact  admixture  of  blue,  red,  and  yellow,  he  would  fail,  and 
would  produce  instead  a  black,  or  deep  brown  ;  but  this  would 
not  be  a  proper  application  of  the  law  above  stated.  Never- 
theless, to  a  certain  extent,  the  practice  of  producing  white  by 
the  combining  of  the  three  colors,  is  had  recourse  to  every  day 
by  the  practical  bleacher  and  dyer.  All  goods  coming  from 
the  bleaching  process,  no  matter  what  the  nature  of  the  process 
has  been,  have  always  a  brownish  yellow  tinge:  to  cotton  goods, 
a  little  indigo  or  cobalt  blue  is  added,  and  the  result  is,  a  much 
purer  white;  to  silk,  which  has  much  more  of  the  yellow  tinge 
than  cotton,  a  little  Prussian  blue  and  cochineal  pink,  or  what 
is  more  common,  a  little  archil,  which  gives  a  violet  color,  is 
added,  the  quantity  varying  according  to  the  depth  of  yellow 
— the  result  is  a  beautiful  white. 

The  following  simple  experiment  serves  to  illustrate  how 
far  the  production  of  colors  depends  upon  the  relation  of  the 
substance  to  light:  Take  a  solution  of  iodide  of  potassium, 
which  is  colorless  and  transparent,  and  divide  it  into  three  pro- 
portions; into  the  one  pour  a  little  acetate  of  lead  (sugar  of 
lead),  into  the  other  a  persalt  of  mercury,  and  into  the  third  a 
little  starch,  with  a  few  drops  of  nitric  acid.  These  are  all 
colorless  substances;  but  after  they  are  mixed,  in  the  first  we 
have  a  deep  and  beautiful  yellow ;  in  the  second  a  red  ;  and  in 
the  third  a  blue.  Thus  we  have  the  three  primitive  colors 
produced  by  the  same  substance  combining  with  other  sub- 
stances, all  previously  colorless.  Many  white  flowers,  when 
macerated  in  water,  yield  a  yellow  color,  which  alkalies  turn 
green  and  acids  red. 

Effects  of  different  Eays  upon  Colors. — The  three 
separate  rays  of  light  have  peculiarities  of  action  :  one  has  heat- 
ing power,  and  is  therefore  termed  the  calorific  ray ;  another 
has  more  of  the  property  of  giving  light,  and  is  termed  the 
luminous  ray  ;  and  the  third  has  the  greatest  effect  in  changing 
the  composition  of  bodies,  and  is  in  consequence  termed  the 
chemical  ray.  But,  in  our  remarks  upon  the  effects  produced 
by  light,  we  will  speak  of  their  total  action. 

The  effects  of  heat  upon  dyed  colors,  which  we  have  already 
described,  are  equally  applicable  to  light,  the  presence  of  mois- 
ture greatly  facilitating  the  effects.    Eeds,  dyed  by  Brazil- 


28  EFFECTS  OF  LIGHT  CAUSING  COMBINATION. 


wood  and  a  tin  mordant,  exposed  to  light,  pass  into  a  brownish 
orange,  and  then  gradually  fade  away.  Prussian  blue  becomes 
reddish,  and  passes  into  a  dirty  gray.  Yellows  become  brown, 
and  then  fade.  The  effects  of  light  and  moisture  are  beautifully 
shown  by  taking  a  piece  of  Prussian  blue  dry,  and  another 
wet,  and  placing  each  under  a  glass,  exposed  to  the  rays  of  the 
sun  for  a  day.  The  wet  piece  becomes  a  reddish  lavender, 
while  the  dry  piece  is  very  little  affected.  Safflower  colors 
are  easily  affected  by  light,  but  more  so  when  wet;  so  that 
when  such  colors  are  being  dried  in  the  air,  care  should  be 
taken  to  keep  them  from  exposure  to  light. 

The  action  of  light  upon  different  matters  and  colors,  and 
its  power  of  changing  the  constitution  of  these  substances, 
have  recently  formed  the  subject  of  a  distinct  branch  of  che- 
mical study,  known  by  the  name  of  actino  chemistry.  Mr.  Eobert 
Hunt,  who  has  done  a  good  deal  in  this  department  of  chemi- 
cal science,  says:  "The  changes  produced  by  the  influence  of 
the  solar  rays  are  of  a  remarkable  character,  and  few  of  them, 
in  the  present  state  of  our  knowledge,  can  be  satisfactorily 
explained.  In  some  instances  it  would  appear  that  new  pro- 
perties are  imparted  to  bodies  by  exposure  to  sunshine  ;  in 
others  that  radiation  has  the  power  of  disturbing  the  known 
chemical  forces,  and  apparently  establishing  a  new  order  of 
affinities;  whilst,  in  all,  we  are  forced  to  recognize  the  opera- 
tions of  a  principle,  the  nature  of  which  is  involved  in  the 
most  perplexing  uncertainty." 

Effects  of  Light  causing  Combination. — We  will  here 
refer  to  a  few  examples  of  the  action  of  light  upon  substances, 
and  the  power  it  possesses  of  inducing  changes,  with  a  view  to 
impress  upon  the  practical  man  the  necessity  of  a  strict  atten- 
tion to  all  the  conditions  and  circumstances  in  which  he  may 
have  to  place  his  colored  fabrics  and  coloring  materials.  In 
many  cases  bodies  remain  mixed  and  without  action  upon  each 
other  in  the  dark,  but  combine  rapidly  and  form  new  com- 
pounds when  exposed  to  light.  Thus,  chlorine  and  hydrogen 
may  be  kept  mixed  in  the  dark  for  any  length  of  time;  but,  if 
exposed  to  daylight,  they  silently  combine  and  form  muriatic 
acid.  If  the  mixture  be  exposed  to  strong  sunshine,  the  com- 
bination becomes  so  rapid  as  to  cause  an  explosion. 

Chlorine,  in  water,  remains  a  long  time  unaltered  in  the  dark, 
but  by  exposure  to  light  the  water  is  decomposed,  muriatic  acid 
is  formed,  and  oxygen  given  off.  These  effects  are  observed 
daily  in  the  operations  of  bleaching.  If  gray  goods  are  put 
into  the  bleaching  liquor,  and  kept  in  the  dark,  they  whiten 
much  more  slowly  than  when  exposed  to  light.   Many  bleachers 


LIGHT  DECOMPOSES  CHEMICAL  COMPOUNDS. 


29 


know  this,  and  expose  their  goods  to  light,  and  keep  their 
bleaching  vessels  in  the  lightest  part  of  the  premises. 

Mixtures  of  chlorine  with  carbonic  oxide,  of  chlorine  with 
sulphurous  acid,  and  chlorine  with  pyroxylic  spirit,  and  many 
other  substances,  are  similar  examples  of  the  same  kind,  being 
all  inactive  upon  each  other  in  the  dark,  but  combining  easily 
and  rapidly  when  exposed  to  light. 

Light  decomposes  Chemical  Compounds.— Chemical  com- 
pounds are  also  decomposed  by  exposure  to  light.  Carbonic 
acid  gas,  exposed  to  strong  sunshine,  is  decomposed  into  oxygen 
and  carbon.  This  decomposition  is  supposed  to  go  on  daily  in 
vegetable  bodies  during  their  growth,  causing  them  to  give  off 
oxygen  and  take  up  carbon.  Colorless  nitric  acid,  exposed  to 
the  sun,  soon  becomes  yellowish-brown,  from  a  portion  of  it 
being  decomposed,  and  the  red  nitrous  fumes  remaining  in  the 
acid  produce  the  color — which  again  shows  the  propriety  of 
keeping  the  carboys  with  that  acid  in  the  shade  as  much  as  pos- 
sible, as  such  changes  by  the  sun's  rays  materially  affect  the 
preparation  of  many  of  the  dying  compounds,  and  also  the 
strength  of  the  acid. 

Nitrate  and  chloride  of  silver,  both  white  salts,  become  black 
by  exposure  to  light;  paper  or  cloth  saturated  with  these  salts, 
and  exposed  to  light,  is  dyed  permanently  black.  This  is  the 
principle  of  the  art  of  photography,  which  consists  in  expos- 
ing a  piece  of  paper  saturated  with  such  salts,  with  a  leaf  or 
picture  interposed  between  the  light  and  the  paper;  an  impres- 
sion of  the  leaf  or  picture  is  thus  obtained;  and,  by  washing 
the  paper  afterwards  in  a  solution  of  hyposulphite  of  soda,  or 
weak  ammonia,  all  the  silver  not  affected  or  decomposed  by 
the  light  is  dissolved  and  removed,  and  the  picture  thus  fixed. 
A  piece  of  paper  prepared  with  a  solution  of  silver,  and  exposed 
to  the  colored  rays  passing  through  a  prism  as  described  (page 
25)  is  affected  thus: — 

Names  of  colored  ray.  Changes  on  paper  prepared. 

Violet  Purplish  black. 

Indigo  Black  not  so  purplish. 


These  results  are  exceedingly  curious  and  interesting,  and 
may  point  out  some  useful  application  in  respect  to  the  pre- 
serving of  compounds  from  change,  by  keeping  them  in  vessels 
which  admit  those  rays  only  which  least  affect  them. 


Blue  . 
Green 
Yellow 
Orange 


Eed 


Black. 
Green. 
Eed. 

Faint  brick  red. 
No  change. 


30  PRACTICAL  APPLICATION  OF  THE  PRINCIPLES. 


Bichromate  of  potash  put  upon  cotton  fibre  becomes  dark 
brown  by  exposure  to  light. 

Chromate  of  copper,  a  brown  substance,  passes  into  white 
by  exposure  to  the  sun's  rays. 

Solutions  of  substances  are  also  affected  by  the  sun's  rays, 
sometimes  sufficiently  to  cause  a  precipitation.  A  solution  of 
protosulphate  of  iron  (copperas)  in  distilled  water,  may  be  kept 
a  long  time  clear  in  the  dark;  but,  when  exposed  to  sunshine, 
it  becomes  cloudy,  and  oxide  of  iron  precipitates.  A  solution 
of  bichromate  of  potash,  exposed  to  the  sun's  rays,  acquires  a 
property  of  precipitating  many  metals,  as  chromates,  much 
darker  than  will  be  produced  by  a  similar  solution  kept  in  the 
dark.  The  reddening  and  darkening  of  chrome  colors,  by  ex- 
posure to  light,  is  well  known  to  dyers.  The  great  effects  of 
light  upon  precipitates  are  well  known  to  the  manufacturers  of 
lakes — which,  let  it  be  borne  in  mind,  are  simply  the  coloring 
matter  which  constitutes  the  dyes,  precipitated  and  dried — and 
therefore  the  effect  produced  upon  these  precipitates  is  equally 
true  of  the  same  colors  as  dyes.  Sir  H.  Davy  gives  the  fol- 
lowing anecdote  of  a  maker  of  carmine,  a  lake  made  from 
cochineal : — 

"A  manufacturer  of  carmine,  who  was  aware  of  the  supe- 
riority of  the  French  color,  went  to  Lyons  for  the  purpose  of 
improving  his  process,  and  bargained  with  the  most  celebrated 
manufacturer  in  that  city  for  the  acquisition  of  his  secret,  for 
which  he  was  to  pay  £1000.  He  was  shown  all  the  process, 
and  saw  a  most  beautiful  color  produced,  but  he  found  not  "the 
least  difference  in  the  French  mode  of  fabrication  and  that 
which  had  been  constantly  adopted  by  himself.  He  appealed 
to  his  instructor,  and  insisted  that  he  must  have  kept  some- 
thing concealed.  The  man  assured  him  he  had  not,  and  invited 
him  to  inspect  the  process  a  second  time.  He  minutely  exa- 
mined the  water  and  the  materials,  which  were  in  every  respect 
similar  to  his  own;  and  then,  very  much  surprised,  said:  'I  have 
lost  both  my  labor  and  my  money,  for  the  air  of  England  does 
not  admit  us  to  make  good  carmine.'  4  Stay,'  said  the  French- 
man, 1  don't  deceive  yourself;  what  kind  of  weather  is  it  now?' 
'A  bright  sunny  day,7  replied  the  Englishman.  'And  such  are 
the  days,' said  the  Frenchman,  4  on  which  I  make  ray  color ; 
were  I  to  attempt  to  manufacture  it  on  a  dark  and  cloudy  day, 
my  results  would  be  the  same  as  yours.  Let  me  advise  you, 
my  friend,  only  to  make  your  carmine  on  bright  sunny  days.'" 

Practical  Application  of  the  Principles. — In  the  ap- 
plication of  some  of  these  phenomena  to  the  trade,  we  must 
pause  and  inquire  experimentally  how  this  can  be  effected. 
For  instance,  if  we  dissolve  a  piece  of  iron  in  nitric  acid,  and 


PRACTICAL  APPLICATION"  OF  THE  PRINCIPLES. 

expose  a  portion  of  this  solution  for  some  time  for  the  rays  of 
the  sun,  and  keep  the  other  portion  in  the  dark,  on  adding  a 
solution  of  prussiate  of  potash  to  each  of  these,  the  precipitate, 
formed  by  the  portion  exposed  to  light  will  be  much  deeper  in 
color  than  that  kept  in  the  dark.  Were  we  to  reason  directly 
from  the  result,  we  would  expose  our  nitrate  of  iron  solutions 
to  the  light,  in  order  to  have  a  deeper  dye;  but  if  we  test  this 
by  experiment,  and  dye  a  piece  with  each  of  the  iron  solutions, 
it  will  be  found  that  the  darkest  blue  is  obtained  from  the  iron 
solution  kept  in  the  dark.  Thus,  we  observe,  without  experi- 
ment we  may  be  liable  to  reason  falsely.  The  change  effected 
upon  the  iron  by  the  light  may  make  it  less  fit  to  enter  within 
the  pores  or  cells  of  the  fibre;  or  if  the  combination  of  the  stuff* 
and  fibre  be  affinity,  these  relations  are  affected ;  which  we  will 
discuss  more  fully  in  another  part  of  this  work. 

These  brief  notices  of  the  more  prominent  effects  of  light 
upon  colors,  and  other  compounds,  will  serve  to  impress  the 
dyer  with  the  importance  of  attending  to  what  he  too  often 
considers  trifling  circumstances;  and  to  show  that  while  every 
different  condition — the  moisture  of  the  air,  the  temperature, 
the  degree  of  light,  &c,  are  all  acting  and  reacting  upon  the 
substances  composing  his  colors,  both  before  and  after  they  are 
fixed  upon  the  fabric,  nothing  should  be  considered  too  trifling 
or  of  too  little  consequence  to  warrant  its  being  overlooked. 

The  consideration  of  the  chemical  changes  which  are  sup- 
posed to  be  taking  place  in  the  vegetable  kingdom  through  the 
influence  of  light,  will  be  more  fully  explained  when  we  are 
treating  of  the  coloring  matters  of  vegetables. 

In  connection  with  light,  there  is  an  application  of  a  very 
important  practical  kind  which  it  will  be  well  to  notice,  namely, 
the  arrangement  of  colors,  so  that  their  harmony  should  pro- 
duce the  best  effect.  Upon  this  subject  many  propositions  were 
made  for  the  decoration  and  laying  out  the  manufactures  in  the 
Great  Exhibition.  Upon  the  philosophy  of  the  arrangement 
of  different  colors  for  effect,  we  will  quote  from  the  Athenceum 
(Athen.  1851,  p.  273)  a  few  passages  upon  this  subject,  which 
we  think  will  be  useful  to  the  dyer: — 

"The  Successive'  contrast  has  long  been  known  ;  and  it  con- 
sists in  the  fact,  that  if,  you  look  steadfastly  for  a  few  minutes 
on  a  red  surface  fixed  on  a  white  sheet  of  paper,  and  then  carry 
your  eye  to  another  white  sheet,  you  will  perceive  on  it  not  a 
red  but  a  green  one;  if  a  green,  red;  if  purple,  yellow;  if  blue, 
orange.  The  1  simultaneous'  contrast  is  the  most  interesting 
and  useful  to  be  acquainted  with.  When  two  colored  surfaces 
are  in  juxtaposition,  they  mutually  influence  each  other — favor- 
ably, if  harmonizing  colors,  or  in  a  contrary  manner  if  discord- 


32 


PRACTICAL  APPLICATION  OF  THE  PRINCIPLES. 


ant;  and  in  such  proportion  in  either  case  as  to  be  in  exact  ratio 
with  the  quantity  of  complementary  color  which  is  generated 
in  our  eye.  For  example,  if  two  half-sheets  of  plain  tint-paper 
— one  dark  green,  the  other  red — are  placed  side  by  side  on  a 
gray  piece  of  cloth,  the  colors  will  mutually  improve,  in  conse- 
quence of  the  green  generated  by  the  red  surface  adding  itself 
to  the  green  of  the  juxtaposed  surface — thus  increasing  its  in- 
tensity— the  green  in  its  turn  augmenting  the  beauty  of  the 
red.  This  effect  can  easily  be  appreciated,  if  two  other  pieces 
of  paper  of  the  same  colors  are  placed  at  a  short  distance  from 
their  corresponding  influenced  ones,  as  below: — 

RED.  RED  GREEN.  GREEN. 

It  is  not  sufficient  to  place  complementary  colors  side  by  side 
to  produce  harmony  of  color,  the  respective  intensities  having 
a  most  decided  influence ;  thus  pink  and  light  green  agree— 
red  and  dark  green  also;  but  light  green  and  dark  red,  pink 
and  dark  green  do  not;  therefore,  to  obtain  the  maximum  of 
effect  and  perfect  harmony,  the  following  colors  must  be  placed 
side  by  side,  taking  into  account  their  exact  intensity  of  shade 
and  tint: — 

HARMONIZING  COLORS. 


Primitive  Colors.  Secondary  Colors. 

r  Light  Blue. 

Eed  Green  .  .  .  .  <  Yellow. 

(Red. 
(  Red. 

Blue  Orange  .  .  .  <  Yellow. 

(Blue, 
f  Blue. 


Yellow  orange  .  .  .  Indigo  .  .  .  <  Red. 

(Yellow. 
TRed. 

Greenish  yellow  .  .  Violet.  .  .  .  <  Blue. 

(Yellow. 
(Yellow. 

Black  White   .  .  .  <  Blue. 

(Red. 

u  If  respect  is  not  paid  to  the  arrangement  of  colors  according 
to  the  above  diagram,  instead  of  colors  mutually  improving 
each  other,  they  will,  on  the  contrary,  lose  in  beauty:  thus,  if 
blue  and  purple  are  placed  side  by  side,  the  blue  throwing  its 
complementary  color,  orange,  upon  the  purple,  will  give  it  a 
faded  appearance;  and  the  blue  receiving  the  orange-yellow  of 
the  purple,  will  assume  a  greenish  tinge.    The  same  may  be 


PRACTICAL  APPLICATION  OF  THE  PRINCIPLES. 


said  of  yellow  and  red,  if  placed  in  juxtaposition.  The  red, 
by  throwing  its  complementary  color,  green,  on  the  yellow, 
communicates  to  it  a  greenish  tinge;  the  yellow,  by  throwing 
its  purple  hue,  imparts  to  the  red  a  disagreeable  purple  appear- 
ance. It  is  of  very  great  importance  that  every  one  should  be 
acquainted  with  the  laws  of  colors  who  intends  to  display  or 
arrange  colored  goods  or  fabrics. 

"The  mixed  contrast  gives  the  reason  why  a  brilliant  color 
should  never  be  looked  at  for  any  length  of  time  if  its  true 
tint  or  brilliancy  is  to  be  appreciated ;  for  if  a  person  looks, 
for  example,  at  a  piece  of  red  cloth  for  a  few  minutes,  green, 
its,  complementary  color,  is  generated  in  the  eye,  and  adding 
itself  to  a  portion  of  the  red,  produces  black,  which  tarnishes 
the  beauty  of  the  red.  This  contrast  explains  why  the  shade 
of  a  color  may  be  modified  according  to  the  color  which  the 
eye  has  previously  looked  at,  either  favorably  or  otherwise. 
An  example  of  the  first  instance  is  noticed  when  the  eye  first 
looks  to  a  yellow  substance  and  then  to  a  purple  one;  and  as 
exemplifying  the  second  case,  looking  at  a  blue  and  then  at  a 
purple." 


3 


34 


ELEMENTS  OF  MATTER. 

I 

Differences  between  an  Element  and  Compound. — It 
has  been  intimated  that  the  conditions  of  matter — solidity, 
fluidity  and  gasuity — depend  upon  heat;  and  it  was  also  stated 
that,  in  each  state,  there  is  a  vast  variety — a  variety  so  great 
that  the  idea  of  telling  where  their  conditions  begin  and  end 
is  a  task  seemingly  beyond  human  power.  Nevertheless,  by 
labor,  by  experiment,  and  comparison,  much  has  been  done 
not  only  to  distinguish  every  variety  of  substance,  but  why 
one  substance  differs  from  another  both  in  appearance  and 
quality.  Let  us  take  a  known  compound  as  an  illustration: 
When  a  piece  of  steel  is  placed  into  diluted  sulphuric  acid, 
the  acid  dissolves  the  greater  part  of  it;  but  there  is  left  un- 
dissolved a  black  matter,  which,  by  testing,  we  find  to  be  char- 
coal or  carbon,  and  that  which  has  been  dissolved  is  iron.  We 
therefore  infer  that  steel  is  composed  of  iron  and  charcoal — 
that  it  is  a  compound  substance;  but  if  we  take  the  carbon, 
and  treat  it  in  any  way  within  our  power,  we  find  it  still  the 
same,  without  components.  In  the  same  manner  let  us  test 
iron — dissolve  it,  melt  it,  or  treat  it  as  we  will,  it  yields  nothing 
but  iron.  All  such  substances,  then,  that  resist  every  effort  to 
decompose,  or  show  any  admixture,  are  termed  elementary;  or 
simple  substances.  The  number  of  such  elements  known  to 
the  chemist  at  the  present  time  are  sixty  two,  and  all  the  varie- 
ties in  which  we  find  matter  presenting  itself  to  us — whether  in 
the  mineral,  the  vegetable,  or  the  animal  kingdom — are  made 
up  of  one,  or  a  mixture  of  two  or  more  of  those  sixty-two  ele- 
ments. The  following  table  gives  the  names  and  particulars 
necessary  to  be  observed  in  the  study  of  these  elements  : — 


Aluminum  . 

.  Al 

13.7 

Carbon  .  . 

.  C 

6 

Antimony  . 

.  Sb 

129 

Cerium  .  . 

.  Ce 

47 

Arsenic  .  . 

.  As 

75 

Chlorine 

.  CI 

35.5 

Barium  .  . 

.  Ba 

68.5 

Chromium  . 

.  Cr 

26.2 

Beryllium  . 

.  Be 

4.7 

Cobalt   .  . 

.  Co 

29.5 

Bismuth 

.  Bi 

213 

Copper  .  . 

.  Cu 

31.7 

Boron    .  . 

.  B 

11 

Didymium  . 

.  D 

Bromine 

.  Br 

80 

Erbium  .  . 

.  E 

Cadmium  . 

.  Cd 

56 

Fluorine 

.  Fl 

19. 

Calcium .  . 

.  Ca 

20 

Gold  .    .  . 

.  Au 

197 

DIFFERENCES  OF  AN  ELEMENT  AND  COMPOUND.  35 


Hydrogen  . 

.  H 



1 

Rhodium  . 

.  R 

52.2 

Iodine  . 

.  I 



127 

Ruthenium 

.  Ru 



52.2 

Iridium  .  . 

.  Tr 

— 

99 

Selenium  . 

.  Se 



39.5 

Iron  . 

.  Fe 

— 

28 

Silicium 

.  Si 



21.3 

Lanthaniurn 

.  La 

Silver    .  . 

.  Ag 

o 

108.1 

Lead  .    .  . 

.  Ph 



103.6 

Sodium  .  . 

.  Na 



23 

Lithium  . 

.  Li 



6.5 

Strontium  . 

.  Sr 



43.8 

Magnesium 
Manganese  . 

•  Mg 



12 

Sulphur.  . 

.  S 



16 

.  Mn 

b= 

27.6 

Tantalum  . 

.  Ta 



184 

Mercury 

•  Hg 

B 

100 

Tellurium  . 

.  Te 



64.2 

Molybdenum 

.  Mo 

BS 

46 

Terbium 

.  Tb 

Nickel  .  . 

.  Ni 

BS 

29.6 

Thallium  . 

.  Tl 

Niobium  . 

.  Nb 

Thorium 

.  Th 



59.6 

Nitrogen 

.  N 

14 

Tin    .    .  . 

.  Sn 



59 

Osmium 

.  Os 



99.6 

Titanium  . 

.  Ti 

25 

Oxygen .  . 

.  0 

as 

8 

Tungsten  . 

.  W 

92 

Palladium  . 

.  Pd 

53.3 

Uranium 

.  U 

60 

Pelopium  . 

.  Pe 

Yanadium  . 

.  V 

68.6 

Phosphorus 

.  P 

32 

Yttrium .  . 

.  Y 

32.2 

Platinum  . 

.  Pt 

98.7 

Zinc  .    .  . 

.  Zn 

32.6 

Potassium  . 

.  K 

39.2 

Zirconium  . 

.  Zr 

22.4 

When  two  or  more  of  these  elements  combine  together,  it 
is  found  that  the  union  does  not  take  place  indeterminately, 
but  always  in  definite  proportions.  These  proportions  are  ex- 
pressed by  the  figures  placed  opposite  to  the  names  in  the 
above  table.  For  example,  if  we  mix  together  one  ounce  of 
hydrogen  and  one  ounce  of  oxygen,  and  bring  them  under 
circumstances  to  cause  combination,  it  is  found  that  the  one 
ounce  of  oxygen  has  combined  with  an  eighth  part  of  the 
hydrogen,  or  two  drachms,  and  that  other  seven  ounces  of 
oxygen  are  required  to  combine  with  the  whole  of  the  hydro- 
gen. Their  combining  properties  are  therefore  set  down  as  1 
to  8.  The  same  law  holds  good  for  every  other  element ;  so 
that  the  union  is  invariably  distinct  and  definite.  One  ele- 
ment, however,  is  often  found  to  combine  with  another  in  a 
greater  number  of  proportions  than  one  to  one.  Thus,  sup- 
pose nitrogen — which,  according  to  the  table,  has  a  combin- 
ing weight  of  14 — combines  with  oxygen  in  proportions  as 
under : — 

One  nitrogen  =  14  to  one  oxygen    ==  8. 
One  nitrogen  =  14  to  two  oxygen    =  16  two  times  8. 
One  nitrogen  =  14  to  three  oxygen  =  24  three  times  8. 
One  nitrogen  =  14  to  four  oxygen  =  32  four  times  8. 
One  nitrogen  =  14  to  five  oxygen    =  40  five  times  8. 

Thus  we  observe  that  the  proportion  of  oxygen  is  always  8,  or 


36 


USE  OF  SYMBOLS. 


a  multiple  of  8  ;  so  it  is  with  nitrogen,  always  14,  or  twice  14, 
and  so  on  to  any  number  of  multiples  of  14.  ■  The  same  rule 
holds  good  with  every  element  in  the  table ;  they  combine  only 
according  to  the  number  following  the  name. 

But  when  they  thus  combine  in  different  and  distinct  quan- 
tities, the  compounds  formed  are  also  distinct  and  definite. 
Thus,  one  portion  of  nitrogen  and  one  oxygen  is  laughing  gas  ; 
and  it  is  so  at  all  times  and  under  all  circumstances,  and  can 
be  nothing  else.  But  when  two  of  oxygen  combine  to  one  of 
nitrogen,  a  different  substance  is  formed  from  laughing  gas, 
also  distinct  and  definite  from  every  other  proportion  in  which 
the  elements  unite.  The  first  and  last  of  the  above  list  is  an 
apt  illustration — the  former  being  laughing  gas,  the  latter 
aquafortis — nitric  acid. 

Use  of  Symbols. — The  letters  placed  immediately  after  the 
names  of  the  elements  in  the  above  table,  are  the  symbols  com- 
monly used  to  represent  the  respective  elements,  and  facilitate 
the  expression  of  the  compounds  into  which  they  enter. 
Thus,  to  represent  laughing  gas,  we  write  NO,  which  means 
one  of  nitrogen  and  one  of  oxygen.  The  symbol  always  repre- 
sents the  weight  of  the  proportion,  as  given  in  the  table;  and 
the  figures  attached  show  how  often  that  proportion  is  re- 
peated. Thus,  the  formula  for  aquafortis,  N05,  which  means 
one  part  of  nitrogen  and  five  of  oxygen — the  figure  being 
placed  immediately  after  the  symbol  which  is  multiplied. 
Were  there  two  of  nitrogen  and  one  of  oxygen,  the  formula 
would  be  N20;  but  sometimes  there  may  be  two  or  more  pro- 
portions of  a  compound  combined  with  another  compound  ; 
this  is  represented  by  placing  the  figure  before  the  compound 
to  be  multiplied,  and  a  comma  at  the  end.  For  example — two 
proportions  of  aquafortis  united  with  one  of  water  is  expressed 
thus,  2N05,  HO.  The  figure  2  applies  to  all  between  it  and 
the  comma.  Some  use  the  sign  +  instead  of  a  coma — thus, 
2N05  +  HO.  It  being  important  to  the  student  that  these  be 
fully  understood  before  beginning  to  read  for  study,  we  will 
take  another  series  of  compounds  : — 

S03  one  sulphur,  three  oxygen,  sulphuric  acid. 

S03+HO  sulphuric  acid  with  one  water. 

2SO3+HO  two  sulphuric  acid  with  one  water. 

SO3  +  2HO  sulphuric  acid  and  two  water. 

S03+-3HO  sulphuric  acid  and  three  water. 

S03  +  FeO  or  S03,  FeO  sulphuric  acid  and  oxide  of  iron. 

S03FeO  +  HO  sulphuric  acid,  oxide  of  iron,  and  water. 

S03FeO  +  5HO  sulphuric  acid,  oxide  of  iron,  and  five  water. 

8SO3,  Fe203  +  9HO,  here  we  have  three  of  sulphuric  acid, 


CHEMICAL  NOMENCLATURE. 


37 


two  of  iron,  three  of  oxygen,  and  nine  water,  which  is  the 
formula  of  one  of  the  salts  of  iron. 

To  make  up  the  equivalent  weight  of  any  compound  from 
symbols,  we  have  simply  to  multiply  the  elements  given  ac- 
cording to  the  table.  Thus,  suppose  we  take  the  sulphuric 
acid  and  two  water,  which  is  strong  vitriol,  we  have 

One  sulphur  equivalent  weight,    16    =  16 

Three  oxygen  8x3    =  24 

Two  water  ...  1  hy.  and  8  oxygen  ...    =9x2    =  18 

58 

which  is  the  proportion  or  weight  of  sulphuric  acid  of  the 
strength  which  would  be  required  to  combine  with  any  other 
element,  suppose  iron,  which  is  28;  therefore  it  would  require 
fully  twice  the  weight  of  sulphuric  acid  of  this  strength  to 
that  of  a  piece  of  iron  to  dissolve  it. 

The  following  formula  of  crystallized  alum  will  serve  as  an 
exercise  for  the  student  upon  the  symbols  and  equivalents  : — 

KOS03,  A1203  3S03  +  24HO. 

Some  chemists,  instead  of  using  0  for  oxygen,  express  it  by  a 

simple  . — thus  sulphuric  acid  will  be  S,  or  the  alum — 

KS  Al2  3S  24H. 

Nomenclature. — In  the  nomenclature  of  these  elements  in 
the  above  table  there  has  been  no  definite  rule,  being  named 
either  from  the  fancy  of  the  discoverer,  or  from  some  leading 
property  or  appearance  they  present,  which  will  be  noticed  un- 
der their  separate  descriptions;  but,  in  naming  compounds,  a 
distinct  rule  has  been  adopted,  so  that  the  name  of  the  com- 
pound expresses,  as  nearly  as  possible,  its  composition  and  pro- 
perty. We  will  give  a  few  of  the  leading  principles  observed 
in  this  rule  of  naming  compounds. 

Rules  for  Naming  Compounds. — When  two  elements  com- 
bine together,  and  the  compound  formed  has  not  acid  properties, 
the  name  ends  in  ide,  such  as  oxide,  chloride,  bromide,  iodide,  &c. 
Sometimes  uret  is  used  instead  of  ide,.  such  as  in  sulphuret,  car- 
buret, phosphuret,  &c. ;  but  ide  is  now  most  generally  adopted 
even  for  these,  giving  sulphides,  carbonides,  phosphides,  &c.  When 
the  compound  formed  by  the  union  of  the  elements  has  acid 
properties,  the  name  ends  in  ic,  or  ous  ;  thus  we  have  sulphuric, 
sulphurous,  nitric,  nitrous,  chloric,  and  chlorous  acids ;  but  these 
elements,  uniting  together  in  different  multiples,  have  prefixes 
added  to  express  the  number  of  proportions.    Thus,  proto  de- 


38 


CHEMICAL  NOMENCLATURE. 


notes  one  proportion,  or  first;  devto,  or  bi,  two  proportions; 
trito,  three  proportions ;  per  denotes  no  particular  number  only 
the  highest  proportion.  As  examples,  take  the  compounds 
of  hydrogen  and  nitrogen,  already  noticed : — 

NO  protoxide  of  nitrogen. 
N02  binoxide  of  nitrogen. 
N03  nitrous  acid. 
N04  peroxide  of  nitrogen. 
NO,,  nitric  acid. 

Thus,  we  observe,  the  full  name  of  the  substance  not  having 
acid  properties  denotes  its  composition.  In  the  case  of  acids, 
it  does  not  tell  the  number  of  elements  combined,  as  with  ox- 
ides— ous  simply  signifying  that  it  has  less  oxygen  than  another 
acid  composed  of  the  same  elements,  and  which  ends  in  ic. 
There  are  sometimes  more  than  two  acids  formed  by  the  com- 
bining of  the  same  elements ;  in  this  case,  if  the  oxygen  is  less 
than  in  the  acid  whose  name  terminates  with  ous,  the  prefix 
hypo  is  put  to  the  name  of  the  ous  acid;  if  there  be  more  oxygen 
than  in  the  ous  acid,  and  less  than  the  ic  acid,  the  same  prefix  is 
made  to  the  last-named  acid.  Finally,  when  there  is  more  oxy- 
gen present  than  in  the  acid  whose  name  terminates  with  ic, 
the  prefix  per  is  put  as  in  oxides.  The  following  illustrations 
will  exemplify  these  terms. 

S202  hypo-sulphurous  acid. 
S02  sulphurous  acid. 
S205  hypo-sulphuric  acid. 
S03 sulphuric  acid. 

Any  acid  found  having  more  oxygen,  in  relation  to  the  sul- 
phur, than  the  last  named  in  this  list,  would  be  called  ^er-sul- 
phuric  acid.  It  will  thus  be  seen  that  the  names  of  the  compounds 
denote  their  composition,  and  give  an  idea  of  their  leading  pro- 
perties. The  term  sesqui — as  sesquioxide — is  often  used,  and 
means  one  and  half  of  an  equivalent,  which,  as  may  be  inferred 
from  what  has  been  said,  cannot  take  place.  Nevertheless,  the 
name  is  conveniently  retained  to  denote  such  compounds  as 
have  two  of  one  element  and  three  of  another — such  as  ses-  „ 
quioxide  of  iron,  also  termed  peroxide,  and  which  is  com- 
posed of  two  iron  with  three  oxygen,  Fe203.  Sometimes  one 
proportion  of  oxygen,  chlorine,  &c,  combines  with  two  propor- 
tions of  a  base  as  a  metal;  such  compounds  have  the  prefix 
sub,  or  di  as 

Fe20,  sub-oxide  of  iron,  or  dinoxide  of  iron. 
Cu2Cl,  sub-chloride,  or  dichloride  of  copper. 


CHEMICAL  NOMENCLATURE. 


89 


When  one  proportion  of  oxygen,  chlorine,  &c,  combines  with 
three  of  a  metal,  the  prefix  trisub  or  tridi,  is  occasionally  used, 
but  this  is  not  very  convenient;  the  best  and  most  general  plan 
is  to-denote  such  compounds  as  basic,  and  then  apply  the  ordi- 
nary prefixes,  such  as  bibasic,  tribasic,  &c,  thus: — 

Cu20,  bibasic  oxide  of  copper. 
Cu30,  tribasic  oxide  of  copper. 

In  the  name  of  a  compound  ending  in  ide,  the  base  or  element 
with  which  the  oxygen,  chlorine,  &c,  is  combined,  is  named 
last,  as 

*  Oxide  of  iron.  Oxygen  and  iron. 

Chloride  of  iron.  Chlorine  and  iron. 

Iodide  of  iron.  Iodine  and  iron. 

Oxide  of  sulphur.  Oxygen  and  sulphur. 

Oxide  of  nitrogen.  Oxygen  and  nitrogen. 

But  with  compounds  having  acid  properties,  the  base  is  placed 
at  the  beginning,  thus: — 

Sulphuric  acid.  Sulphur  and  oxygen. 

Nitric  acid.  Nitrogen  and  oxygen. 

Hydrochloric  acid.  Hydrogen  and  chlorine. 

Salts— Their  Nature  and  Nomenclature. — The  acids 
combine  with  other  substances,  as  the  metals,  and  form  another 
*class  of  compounds  termed  Salts.  The  names  of  these  also 
denote  their  composition:  the  salt  formed  between  the  acid  ter- 
minating in  ic  and  a  base,  ends  with  ate;  that  formed  by  the 
acid  terminating  in  ous  ends  with  ite,  the  name  of  the  element 
with  which  the  acid  combines  being  added.  Thus, 

Sulphuric  acid  and  iron  form  sulphate  of  iron. 
Sulphurous  acid  and  iron  .    .  sulphite  of  iron. 

When  these  acids  unite  with  elements  or  bases  in  different  pro- 
portions, the  same  prefixes  are  used  as  with  oxides.  If  one 
proportion  of  acid  unites  with  one  of  another  element,  the  com- 
pound is  termed  proto — as  proto-sulphate  of  iron;  if  two  of  acid 
and  one  metal,  the  compound  has  bi — as  bisulphate  of  iron,  &c. 
Per  is  also  used  as  denoting  the  highest  proportion,  as  when 
three  equivalents  of  acid  unite  with  two  equivalents  of  iron, 
the  salt  is  termed  persulphate  of  iron. 

Sometimes  we  have  the  metal  uniting  with  acids,  forming 
basic  salts,  as  described  in  the  case  of  the  basic  oxides,  such  as 
having  two  proportions  of  metal  to  one  of  acid,  and  three  pro- 
portions or  equivalents  of  metal  to  one  of  acid.  In  such  cases, 
the  same  prefixes  are  used  as  we  have  before  stated,  namely — 


40 


CHEMICAL  NOMENCLATURE. 


hibasic  sulphate  of  copper,  two  equivalents  of  copper  to  one 
of  sulphuric  acid ;  tribasic  sulphate  of  copper,  three  of  copper 
to  one  of  acid. 

Combinations  of  water  with  oxides  or  salts  are  termed  hy- 
drates, or  the  compound  is  termed  hydrous,  in  contradistinction 
to  substances  having  no  water,  which  are  termed  anhydrous — 
thus,  hydrate  of  potash,  or  hydrous  potash,  KO  HO ;  anhy- 
drous potash,  KO. 

Two  salts  sometimes  unite  together,  and  form  a  definite 
compound,  which  is  termed  a  double  salt.  Alum,  as  already 
given,  is  a  good  instance  of  this  class  of  compounds:  it  is  a 
double  salt  of  sulphate  of  alumina  and  sulphate  of  potash. 


41 


CHEMICAL  AFFINITY. 


The  elements  of  matter  have  a  disposition,  if  we  may  use 
the  term,  to  unite  with  one  another ;  this  disposition  is  termed 
affinity,  or  chemical  attraction.  The  affinity  of  any  one  ele- 
ment for  the  others  is  not  equal,  but  is  greater  for  some  one 
element,  or  for  a  particular  class  of  elements.  Thus  oxygen 
has  a  stronger  attraction  for  those  elements,  the  combining  of 
which  forms  alkalies,  than  for  any  of  the  others;  and  amongst 
these  potassium  has  the  strongest  affinity  for  oxygen;  so  that, 
by  the  operation  of  this  law,  should  a  number  of  elements  be 
arranged  together,  under  proper  circumstances  for  combining, 
those  which  have  the  strongest  attraction  for  each  other  will 
combine  first.  The  same  law  holds  good  when  compound 
bodies  unite  together,  such  as  an  acid  with  the  oxide  of  a  metal. 
Were  we  to  take  sulphuric  acid,  and  add  to  it  a  mixture 
of  potash  and  magnesia,  the  acid  would  combine  with  the 
potash  before  it  would  take  the  magnesia;  and  were  there 
enough  of  potash  to  combine  with  the  whole  of  the  sulphuric 
acid,  the  magnesia  would  be  left,  because  the  potash  has  a 
stronger  attraction  for  this  acid  than  magnesia.  This  pecu- 
liarity of  selecting  is  not  merely  owing  to  the  substance  having 
acid  properties,  but  from  a  peculiar  attraction  between  the 
base  and  acid  compounds.  Thus  the  two  acids,  sulphuric  and 
muriatic,  comport  themselves  towards  the  following  bases,  as 
under : — 


Muriatic  Acid. 
Silver, 
Potash, 
Soda, 
Barytes, 
Strontia, 
Lime, 
Magnesia. 

Although  we  have  named  silver  here,  under  the  sulphuric 
acid  column,  in  order  to  complete  the  comparison,  it  is  not 
immediately  next  to  magnesia  in  affinity  for  that  acid;  a  great 
many  of  the  other  metals  rank  before  it,  such  as  mercury, 
iron,  zinc.    So  that,  were  there  a  solution  of  sulphate 


Sulphuric  Acid. 
Barytes, 
Strontia, 
Potash, 
Soda, 
Lime, 
Magnesia, 
Silver. 


42 


CIRCUMSTANCES  INFLUENCING  AFFINITY. 


of  silver  added  to  a  solution  containing  these,  the  acid  would 
leave  the  silver  and  combine  with  the  mercury,  next  leave  the 
mercury  and  combine  with  copper,  then  leave  the  copper  and 
take  the  iron,  and  lastly,  leave  the  iron  and  take  the  zinc. 

It  is  this  law  of  affinity  that  regulates  compositions  and  de- 
compositions, all  of  which  are  matters  of  daily  experience  in 
the  dye-house,  particularly  that  class  of  decompositions  termed 
double,  in  which  two  salts  being  put  together,  there  takes  place 
a  mutual  exchange  of  partners,  if  we  may  so  term  it.  For 
instance,  in  mixing  nitrate  of  iron  with  yellow  prussiate  of 
potash  :  the  nitric  acid  leaves  the  iron,  and  combines  with  the 
potash,  while  the  iron  and  prussic  acid  combine,  forming 
Prussian  blue.  When  any  of  the  two  compounds  so  combined 
forms  an  insoluble  substance,  the  decomposition  is  always  more 
apparent,  more  complete,  and  most  applicable  to  dyeing  pur- 
poses. Compounds  which  cannot  easily  be  formed,  directly  by 
bringing  their  elements  together,  are  often  formed  by  means 
of  double  decomposition  :  thus  carbonate  of  iron  is  difficult  to 
form  directly,  but  by  mixing  a  solution  of  carbonate  of  soda 
with  sulphate  of  iron,  this  compound  is  instantly  formed, 
which  may  be  thus  represented  : — 

NaO  C02,  FeO  S03  =  FeO  C02,  NaO  S03. 

Application  of  Affinity. — These  double  decompositions 
and  recompositions  are  of  the  utmost  importance  to  the  practi- 
cal dyer,  who  should  make  himself  thoroughly  acquainted  with 
all  their  laws  and  conditions;  as  it  is,  these  formations  of  new 
and  often  insoluble  compounds,  which  constitute  a  prominent 
feature  in  the  production  of  colors,  and  every  circumstance 
connected  with  this  class  of  phenomena,  favors  this  kind  of  re- 
action for  practical  purposes.  It  is  a  general  law  in  ordinary 
affinity,  in  the  union  of  two  elements,  or  of  a  compound  with 
an  element,  such  as  dissolving  a  metal  in  acid,  that  there  is 
always  a  great  evolution  of  heat.  This  circumstance  wTould 
interfere  with  many  dyeing  operations,  both  upon  the  fibre  and 
color ;  but  in  the  double  affinity  referred  to,  where  two  com- 
pounds merely  exchange  elements,  there  is  no  quantity  of  heat 
evolved,  to  interfere  with  the  dyeing  operations  or  fabric.  The 
interchange  of  elements  takes  place  quietly,  so  that  the  dyer 
may  fix  within  th'e  fibres  of  the  most  delicate  material  any 
compound  required  for  the  color. 

Circumstances  influencing  Affinity. — The  force  of 
affinity  is  greatly  influenced  by  the  conditions  in  which  the 
combining  bodies  are  placed,  as  indicated  when  treating  of 
light  and  heat.  Where  the  atoms  of  any  body  are  brought  into 
contact  with  another  body  under  more  or  less  favorable  circum- 


CATALYTIC  INFLUENCE. 


43 


stances,  anything  that  diminishes  the  cohesion  of  the  particles, 
allows  those  of  the  other  body  to  come  into  closer  approxima- 
tion, and  therefore  favors  chemical  union.  Solid  bodies,  in  ge- 
neral, are  without  chemical  action  upon  one  another;  therefore, 
before  any  chemical  change  can  take  place,  it  is  necessary  to 
bring  the  substance  into  a  fluid  state.  This  is  eminently  ne- 
cessary in  all  dyeing  operations,  not  only  for  the  purpose  of 
causing  combination,  but  to  enable  the  particles  to  enter  within 
the  fibres  of  the  cloth,  and  to  be,  while  there,  acted  upon  by  the 
affinity  of  another  body,  also  in  solution,  brought  into  contact 
with  them.  This  is  an  essential  condition  of  all  dye  drugs, 
and  of  all  salts  used  in  dyeing,  either  as  dyes  or  mordants,  and 
must  never  be  lost  sight  of  in  studying  either  its  philosophy 
or  practical  operation  ;  as  anything  that  interferes  with  the  free 
operation  of  these  conditions  or  solubility,  necessarily  retards 
the  process  or  deteriorates  the  dye. 

Catalytic  Influence. — Another  circumstance  or  power 
sometimes  occurring  in  dyeing  operations,  which  interferes  with 
or  directs  chemical  affinity  amongst  the  particles  of  bodies,  is, 
that  one  body  often  induces  a  chemical  change  in  another, 
while  it  undergoes  no  change  itself.  This  kind  of  affinity,  or 
power,  is  termed  Catalysis.  A  good  instance  of  this  is  in 
fermentation  ;  a  little  yeast  put  into  beer  induces  fermentation 
in  all  the  solution,  while  the  yeast  is  not  altered.  If  we  boil 
starch  with  dilute  sulphuric  acid,  the  starch  is  first  changed 
into  gum,  and  then  into  sugar.  Yet,  notwithstanding  these 
changes,  the  sulphuric  acid  is  found  unaltered,  either  in  pro- 
perty or  quantity.  A  great  many  substances  possess  this  pro- 
perty of  catalytic  influence;  and  it  is  not  unlikely  that  fibrous 
materials,  such  as  silk,  woollen,  and  cotton,  possess  it  towards 
many  of  the  vegetable  coloring  matters  used  in  dyeing;  in- 
deed, many  operations  in  the  dye-house  indicate  the  presence 
of  some  such  power.  The  real  nature  of  this  power  is  not 
well  understood;  only  we  know  that  bodies  subject  to  change 
by  catalysis  have  their  particles  held  together  by  a  weak  affi- 
nity, and  therefore  changes  are  less  or  more  easily  effected, 
according  to  the  power  exerted,  to  keep  their  elements  together. 
The  elements  of  many  organic  compounds  seem  held  together 
by  a  balance  of  power  among  them,  so  that  while  another 
substance  put  into  such  a  compound  may  possess  a  sufficient 
attraction  for  some  of  the  elements  in  the  compound,  to  disturb 
this  balance  of  power,  yet  it  may  not  have  sufficient  power  to 
combine  with  them,  but  only  cause  the  whole  elements  to 
rearrange  themselves  in  a  new,  and  probably  more  stable,  form. 
The  study  of  such  reactions  is  of  the  greatest  interest;  and  as 
these  principles  of  action,  in  all  probability,  play  a  prominent 


CONSTITUTION"  OF  SALTS. 


part  in  the  art  of  dyeing,  it  will  be  again  brought  under 
consideration,  when  describing  operations  where  we  think  this 
action  takes  place.  We  may  here  mention,  however,  that  the 
introduction  of  such  a  term  as  catalysis  is  only  considered 
useful  as  bringing  under  one  group  a  certain  class  of  phe- 
nomena ;  but,  indeed,  the  same  may  be  said  of  the  no  less 
useful  term,  affinity.  When  our  knowledge  of  these  hidden 
powers  is  more  extended,  all  those  phenomena  may,  perhaps, 
be  accounted  for,  and  ranged  under  the  operation  of  some  one 
universal  power  or  law,  of  which  at  present  we  know  only  by 
particular  terms. 

Constitution  of  Salts. — It  may  have  been  observed  that, 
in  describing  the  constitution  of  compounds  and  their  nomen- 
clature, we  grouped  the  elements  together,  as  compounds,  in  a 
certain  order,  such  as  sulphate  of  protoxide  of  iron,  FeO  S03. 
This  formula,  by  its  term  and  grouping,  it  may  be  farther  ob- 
served, indicates  that  the  sulphuric  acid  is  combined  with  the 
oxide  of  the  iron,  and  not  directly  with  the  iron  itself.  Now 
there  is  a  difficulty  which  attaches  to  the  nomenclature,  that 
the  formula  is  made  to  indicate  a  certain  definite  arrangement 
pf  particles,  which  is  now  pretty  generally  considered  as  incor- 
rect. However,  it  is  not  intended  to  enter  here  into  the  merits 
of  the  different  views  entertained  by  chemists  regarding  this 
point,  but  briefly  to  give  a  general  idea  as  a  guide  to  the  work- 
man. We  will  take  sulphuric  acid  as  our  first  illustration. 
The  composition  of  this  acid  is  given  S03,  but  S03  is  a  solid 
crystalline  compound,  which  has  no  acid  properties  until  it  is 
combined  with  one  proportion  of  water,  being  then  S03  +  HO, 
or  hydrous  sulphuric  acid.  If  into  this  acid  we  place  a  piece 
of  iron,  the  reaction  may  be  expressed  thus:  S03HO  +  Fe= 
S03FeO  +  H;  or  as  follows: — 

Water  .    .    .    •  |jj  "  Nsv   Hydrogen  Gas. 


Here  we  have  water  decomposed,  to  give  an  atom  of  oxy- 
gen to  the  iron,  forming  an  oxide ;  and  then  we  have  the  acid 
combining  with  this  oxide.  The  same  principle  of  action  is 
ascribed  to  all  metals,  and  used  to  be  described  as  a  sort  of 
disposing  affinity.  The  acid  S03  is  conceived  to  have  such  an 
attraction  for  the  oxide  of  the  metal,  that  it  disposes  both  the 
metal  to  combine  with  oxygen  and  the  oxygen  with  the  metal, 
in  order  that  it  might  unite  with  the  two,  to  form  a  salt.  Sir 
H.  Davy,  with  his  usual  clear  perception  of  all*  chemical  phe- 
nomena, thought  that,  as  sulphuric  acid  S03  had  no  acid  pro- 


Sulphuric  Acid  .  S03 
Iron    ....  Fe... 


Protosulphate  of  Iron. 


SALT  RADICALS. 


45 


perties,  and  was  incapable  of  combining  with  any  body  as  such, 
except  in  union  with  water,  it  was  more  probable  that  what  is 
termed  hydrated  sulphuric  acid  S034- HO,  may  be  the  true 
composition  of  sulphuric  acid,  rather  than  S03,  and  ought  to  be 
represented  thus,  S04  +  H,  the  hydrogen  being  the  base  or  metal, 
and  that  its  presence  is  an  essential  qualification  to  the  acid : 
so  that  a  piece  of  iron,  being  put  into  sulphuric  acid,  will  have 
a  reaction  as  under,  S04H4-Fe  =  S04  Fe  +  H: — 

Sulphuric  Acid    -[  *~  Hydrogen  Gas. 

Iron    ....    Fe..  Sulphate  of  Iron. 

Here  we  have  no  supposed  primary-disposing  action,  but  the 
iron  simply  taking  the  place  of  hydrogen,  by  substitution,  in 
virtue  of  S04,  having  a  stronger  affinity  for  it  than  for  the 
hydrogen.  The  same  reaction  explains  the  dissolving  of  any 
other  metal  in  sulphuric  acid.  Names  have  been  proposed  in 
accordance  with  this  theory,  as,  for  instance,  the  S04  is  termed 
sulphion;  therefore,  S04+H,  instead  of  being  termed  sulphuric 
acid,  will  be  sulphionide  of  hydrogen,  and  sulphate  of  iron,  sul- 
phionide of  iron.  Such  names  will  however,  be  very  difficult 
to  be  introduced  into  the  science;  and  although  they  were 
approved  of,  their  use  must  necessarily  be  a  matter  of  gradual 
growth.  As  the  truths  of  these  views  become  apparent,  a  new 
and  improved  nomenclature  may  grow  up  spontaneously. 

The  views  given  above,  of  the  true  formula  of  sulphuric 
acid,  may  be  applied  to  all  hydrated  acids.  Nitric  acid  of  the 
formula  N05  has  never  been  isolated  ;  its  existence  is  merely 
supposed  from  analogy.  There  is  N05  +  HO,  hydrated  nitric 
acid;  but  why  N05  +  HO,  rather  than  N06+H  ?  Any  metals 
dissolving  in  it  only  replace  the  hydrogen.  The  same  with 
muriatic  acid  which  is  a  compound  of  hydrogen  and  chlorine, 
properly  termed  hydrochloric  acid.  In  dissolving  a  metal  in 
this  acid,  the  acid,  not  the  water,  is  decomposed.  Or  if  we 
put  hydrochloric  acid  upon  the  oxide  of  a  metal,  as  soda,  the 
action  is  not  that  of  the  acid  combining  with  the  oxide,  but 
there  is  a  double  decomposition  and  composition,  represented 
by  HC1  HO  +  NaO  =  NaCl  +  2HO.  So  that  bodies  termed 
muriates  are  more  properly  chlorides. 

Salt  Radicals. — There  is  another  thing  necessary  for  the 
student  to  bear  in  mind,  in  reference  to  these  views,  and  the 
nomenclature  resting  upon  them.  The  S04,  N06,  &c,  are 
called  the  Salt  Radicals,  which  term  is  often  used  in  chemical 
books,  and  is  applied  equally  to  a  compound,  such  as  the  above, 
or  to  an  element,  such  as  chlorine.  It  refers  to  any  element, 
or  compound  that  will  form  an  acid  when  combined  with  hydro- 


46 


SALT  RADICALS 


gen,  and  a  salt  when  united  with  a  metal.  There  are  a  great 
many  salt  radicals  which  are  compound  substances,  but  which 
deport  themselves  in  their  reactions  as  elements.  One  emi- 
nent example  of  a  substance  of  this  kind  is  cynogen,  (C2N) 
which  is  the  salt  radical  of  Prussic  acid,  and  which  we  shall 
have  occasion  to  notice  when  treating  of  the  compounds  of 
this  acid  and  the  ferro-prussiates,  so  much  used  in  the  dye- 
house. 

This  view  of  the  constitution  of  salts  is  much  more  simple 
than  that  of  oxides  combining  with  the  acids,  and,  as  it  will 
be  apparent,  reduces  the  compound  bodies,  termed  acids  and 
salts,  into  one  great  class. 

It  also  enables  us  to  account  for  a  remarkable  law  which 
has  been  already  noticed,  namely,  that  bases,  such  as  metals, 
always  unite  with  the  same  number  of  proportions,  or  equiva- 
lents of  acids  or  salt  radicals.  Thus,  if  we  dissolve  protoxide 
of  iron  in  sulphuric  acid,  one  proportion  of  iron  only  com- 
bines with  one  proportion  of  acid,  and  is  represented  by  FeO, 
S04H=Fe  S04,  HO. 

But  if  we  take  the  peroxide  of  iron,  and  dissolve  it  in  sul- 
phuric acid,  we  have  then  three  proportions  of  acid,  thus — 

Fe203, 3S04H=Fe2  3S04HO. 

It  must,  however,  be  borne  in  mind,  that  both  theories  re- 
quire several  hypothetical  conditions  to  be  taken  for  granted, 
to  enable  us  to  account  for  all  the  phenomena  which  take  place 
in  the  actions  of  one  body  upon  another;  and  also,  that  both 
these  views  of  the  constitution  of  salts,  as  to  the  manner  in 
which  the  atoms  or  particles  arrange  themselves,  are  liable  to 
objections.  We  have  stated  the  fundamental  principles  of 
these  views,  both  as  a  general  guide  to  the  student  in  his  inqui- 
ries into  chemical  science,  and  because  we  shall  have  occasion 
to  refer  to  them  hereafter.  But  the  reader  who  wishes  to  ob- 
tain more  extended  information,  may  consult  such  works  as 
those  of  Graham,  Liebig,  Daniell,  Gmelin,  and  others,  who  have 
given  this  matter  much  close  attention  ;  and  such  research  will 
be  found  amply  to  repay  any  labor  and  time  expended  upon  it ; 
for  on  the  proper  understanding  of  the  fundamental  laws  of 
affinity  depends,  in  a  great  measure,  the  proper  application  of 
chemical  science  to  practical  purposes,  and  more  especially  in 
such  delicate  operations,  and  with  such  materials,  as  the  animal 
and  vegetable  fibres  operated  upon  in  a  dye-house. 


ELEMENTARY  SUBSTANCES. 


Oxygen  (0.  8.) 

By  referring  to  the  table  of  elements,  it  will  be  found  that 
several  substances  are  therein  named  which  many  of  our  prac- 
tical readers  have  never  heard  of.  There  are,  indeed,  a  num- 
ber of  elements  of  which  little  more  is  known  than  the  fact  of 
their  existing  in  certain  compounds;  they  have  only  been  seen 
by  the  discoverers  and  a  few  friends,  and  are  as  yet  so  rare, 
and  found  in  such  small  quantities,  that,  under  present  circum- 
stances, their  application  to  any  common  branch  of  manufac- 
ture is  not  thought  of.  Such  substances  we  will  therefore  pass 
over  with  a  very  short  notice,  and  confine  ourselves  more  to 
those  that  are,  or,  so  far  as  their  cost  and  quantities  are  con- 
cerned, may  be  brought  into  common  use.  The  name  of  the 
element  at  the  head  of  this  chapter  is  a  very  familiar  term  in 
the  dye-house,  but  is  applied  so  indiscriminately,  and  so  often 
erroneously,  to  different  substances,  as  to  cause  a  considerable 
misunderstanding  of  its  real  nature  and  properties.  Many  of 
these  erroneous  applications  of  the  name,  and  consequent  con- 
fusion of  ideas,  will  be  noticed  more  appropriately  under 
chlorine,  with  which  gas  oxygen  is  often  identified  in  the  dye- 
house. 

Oxygen  exists  in  Nature  both  free  and  combined;  when  free, 
it  forms  a  colorless  and  transparent  gas,  without  taste  or  smell ; 
it  is  a  little  heavier  than  common  air,  of  which  it  forms  a  part, 
and  is  dissolved  or  absorbed  by  water,  in  the  proportion  of 
from  3  to  4  per  cent,  by  weight.  Its  wide  range  of  affinity  for 
other  elements,  its  presence  in  almost  every  compound,  and  the 
part  it  plays  in  nature,  invest  it  with  an  importance  not  pos- 
sessed by  any  of  the  other  elements.  It  constitutes  more  than 
a  fifth  part  of  the  atmosphere,  as  much  as  eight-ninths  of  the 
water,  and  fully  half  of  the  solid  crust  of  the  globe ;  and  it  is, 
besides,  a  prominent  ingredient  in  all  animal  and  vegetable 
bodies.  The  following  table  shows  its  numerical  importance 
more  precisely : — 

Water  has     ....  8  oxygen  in  9  by  weight. 

The  Air   3      "      in  9  " 

Crust  of  the  Earth  .    .  5     "      in  9  " 

Animals  and  Vegetables  7      "      in  9  " 


48 


HOW  TO  MAKE  OXYGEN"  GAS. 


How  to  make  Oxygen  Gas. — The  name  oxygen  was  given 
to  this  element  from  the  idea  which  the  old  chemists  had,  that 
it  gave  acid  properties  to  its  compounds.  It  was  first  recog- 
nized in  this  country  as  a  distinct  substance  by  Dr.  Priestley, 
in  the  year  1774,  and  about  a  year  after  in  Sweden,  by  Scheele, 
without  any  previous  knowledge  of  Priestley's  discovery.  It 
was  obtained  by  Priestley  by  heating,  in  a  retort,  red  oxide  of 
mercury,  which  is  thereby  resolved  into  fluid  mercury  and  oxy- 
gen. But  other  and  more  economical  means  are  now  adopted 
for  its  preparation,  as  follows:  An  iron  bottle  is  prepared, 
with  an  iron  tube  fitted  into  the  mouth  air-tight,  forming  a 
retort;  into  this  a  quantity  of  black  oxide  of  manganese  is  put, 
and  the  bottle  placed  with  its  contents,  into  a  good  fire,  with 
the  open  end  of  the  iron  pipe  dipping  into  a  vessel  filled  with 
water.    The  following  figure  shows  the  bottle  in  the  fire,  with 


planation  of  what  is  taking  place  within  the  retort-bottle  in  the 
fire  it  may  be  stated,  that  the  black  oxide  of  manganese  is  com- 
posed of  Mn02;  the  high  heat  drives  off,  or  sets  at  liberty,  a 
portion  of  the  oxygen,  and  the  manganese  is  converted  into  a 
lower  state  of  oxidation;  so  that  3Mn02  becomes  Mn03,Mn 


Another  and  more  rapid  method  of  preparing  oxygen  is,  by 
taking  equal  parts  of  oxide  of  copper  and  chlorate  of  potash, 
and  placing  the  mixture  into  a  small  flask  or  test-tube,  fitted 


Fig.  1. 


the  conducting  pipe.  Care  must 
be  taken  not  to  allow  any  of  the 
contents  of  the  bottle  to  get  into 
the  pipe.  When  the  bottle  be- 
comes redhot,  bubbles  of  gas  are 
seen  to  rise  from  the  pipe  through 
thewater;  these  bubbles  are  oxygen 
gas,  and  may  be  collected  by  filling 
a  bottle  or  jar  with  water,  and  hold- 
ing its  mouth  downwards  over  the 
extremity  of  the  pipe;  the  gas  as- 
cending into  the  bottle  or  jar,  grad- 
ually displaces  the  water.    In  ex- 


0  +  20. 


Fig.  2. 


with  a  glass  tube,  as  repre- 
sented by  the  annexed  cut. 
When  heat  is  applied,  by 
means  of  a  lamp,  a  rapid 
evolution  of  gas  takes  place, 
very  pure,  and  without  any 
danger  to  the  operator.  One 
ounce  of  chlorate  of  potash, 
treated  in  this  way,  will 


HYDROGEN. 


49 


yield  about  500  cubic  inches  of  gas.  The  chlorate  of  potash  is 
composed  of  KO  CI  05,  all  the  oxygen  is  set  free,  and  chloride  of 
potassium  left.  The  oxide  of  copper  undergoes  no  decomposition. 
The  part  it  plays  is  not  well  understood ;  but  a  practical  use  of 
its  presence  in  this  experiment  is,  to  prevent  fusion  of  the  salt, 
which  would  take  place,  and  is  liable  to  break  the  vessel  used. 
When  the  experiment  is  finished,  and  the  flask  cold,  a  little 
water  will  dissolve  out  the  chloride  of  potassium  from  the  oxide 
of  copper,  which,  when  dried,  may  be  used  again  for  a  similar 
experiment.  There  are  a  variety  of  other  means  of  obtaining 
this  gas,  but  they  need  not  be  detailed. 

Properties  of  Oxygen. — Oxygen  is  an  eminent  supporter 
of  combustion.  If  a  candle  be  placed  in  an  atmosphere  of  this 
gas,  it  burns  with  intense  brilliancy.  Sulphur  and  charcoal 
being  kindled,  and  placed  in  oxygen,  give  a  vivid  light,  and 
there  is  formed  sulphurous  acid  with  the  sulphur,  and  carbonic 
acid  with  the  charcoal.  If  a  piece  of  iron  or  steel  wire  be  made 
red-hot,  and  then  immersed  into  oxygen  gas,  the  combination 
is  so  rapid,  that  the  heat  produced  causes  the  iron  to  scintil- 
late, and  the  oxide  to  fuse,  and  drop  oft'  like  water,  sufficiently 
hot  to  melt  or  fuse  china  and  glass.  Many  other  metals  burn  in 
the  same  way  as  iron  in  this  gas.  It  is  upon  this  gas  that  depend 
the  processes  of  combustion  and  respiration ;  and  the  various 
functions  of  organized  existence,  in  all  its  forms,  are  essentially 
connected  and  sustained  through  the  agency  of  oxygen.  In- 
deed, there  are  few  operations  in  chemistry  which  are  not  in 
some  way  connected  with  oxygen;  so  that,  under  the  various 
heads  in  which  we  intend  to  treat  our  subject,  its  nature  and 
properties  will  be  constantly  developed.  Dyed  fabrics,  whe- 
ther wet  or  dry,  suspended  in  this  gas,  are  not  affected,  a  fact 
for  the  dyer  to  bear  in  mind  when  he  is  identifying  this  gas 
with  chlorine. 

Hydrogen  (H.  1). 

Hydrogen  is  a  gaseous  element,  never  found  free  or  uncom- 
bined  in  Nature,  but  is  easily  obtained  from  some  of  the  com- 
pounds of  which  it  is  a  component.  When  pure,  it  is  without 
smell  or  color,  and  is  the  lightest  substance  known ;  it  is  there- 
fore used  for  inflating  balloons.  Its  distinctive  character  as 
an  element  was  first  pointed  out  by  Cavendish,  in  1766.  It 
exists  abundantly  in  nature,  in  combination  with  other  ele- 
ments; it  is  a  constituent  of  all  animal  and  vegetable  substances 
and,  being  one  of  the  constitutents  of  water,  it  enters  as  such 
into  the  composition  of  almost  all  compounds.  It  is  from 
4 


50 


WATER. 


FiS  3-  the  decomposition  of  water  that  hydrogen 


is  generally  prepared  for  experimental 
purposes.  The  process  is  simple.  By 
putting  some  iron  or  zinc  into  a  retort, 
and  pouring  over  it  a  little  dilute  sul- 
phuric or  hydrochloric  acid,  the  metal 
dissolves  with  effervescence,  and  the  gas, 
in  passing  off,  may  be  caught  in  bottles  or 
jars  over  the  pneumatic  trough,  as  de- 
scribed for  oxygen.  Instead  of  a  retort,  a 
flask  or  bottle  may  be  used,  having  a  tube 
fitted  by  a  cork  in  the  mouth  of  the  bottle, 


as  represented  by  the  annexed  figure. 
The  reaction  which  takes  place,  by  the  acid  acting  on  the 
metal,  is  as  we  have  before  shown  (page  45), 

S04H  +  Zn  =  S04Zn  +  H. 

We  observe  here  that  the  change  is  only  the  substitution  of 
the  metal  for  the  hydrogen  in  the  acid.  The  use  of  the  water 
mixed  with  the  acid  is  to  dissolve  the  salt  of  zinc  formed  in 
the  process,  which  requires  a  considerable  quantity  of  water. 
From  these  and  similar  facts,  hydrogen  is  supposed  to  be  a 
metal  existing  in  a  gaseous  form.  At  all  events,  its  chemical 
character  exhibits  many  of  the  properties  possessed  by  the 
metals.  Hydrogen,  when  prepared  in  the  way  described,  has 
a  slight  smell,  which  results  from  impurities  in  the  substances 
used,  generally  a  small  trace  of  arsenic,  or  sulphur,  in  the 
metal.  When  iron  is  used  instead  of  zinc,  the  smell  is  still 
more  perceptible.  Hydrogen  is  a  combustible  gas,  and  burns 
with  a  yellow  flame,  but  does  not  support  combustion.  A 
burning  candle  immersed  in  it  is  instantly  extinguished.  When 
mixed  with  oxygen,  and  heat  is  applied,  the  mixture  explodes 
with  a  loud  report,  and  water  is  formed  by  the  union  of  the 
gases.  Hydrogen  does  not  support  life.  An  animal  immersed 
in  an  atmosphere  of  it  soon  dies.  Several  attempts  have  been 
made  to  breathe  this  gas,  and  some  curious  effects  have  been 
observed ;  but  from  incautiousness  in  not  purifying  the  gas 
perfectly  before  inhaling  it,  two  fatal  accidents  have  followed. 
All  such  attempts  are  extremely  foolish.  Hydrogen  combines 
with  oxygen  in  two  proportions,  forming  the  protoxide  or 
water,  and  peroxide  or  binoxide,  a  substance  which  has  strong 
bleaching  properties. 

Water. — The  discovery  of  the  true  composition  of  water 
was  made  by  Cavendish  in  1781,  by  burning  known  quantities 
of  oxygen  and  hydrogen  in  a  dry  glass  vessel,  and  observing 
that  water  was  formed  and  deposited  on  the  glass,  and  in  quan- 


WATER. 


51 


tity  exactly  equal  to  the  weights  of  the  gases  which  disappeared. 
He  also  found  that  these  gases  unite  exactly  in  the  proportion  of 
two  volumes  of  hydrogen  with  one  of  oxygen,  and  by  weight, 
1  to  8. 

Pure  water  is  colorless  and  transparent,  and  has  neither 
taste  nor  smell.  It  is  eminently  neutral,  having  neither  acid 
nor  alkaline  properties,  and  does  not  alter  the  nature  of  sub- 
stances put  into  it.  It  often  enters,  however,  into  the  compo- 
sition of  compounds;  and  many  substances  put  into  it  have 
the  property  of  decomposing  it,  and  appropriating  its  ele- 
ments. 

The  statement  that  water  is  entirely  neutral,  and  having  no 
action  upon  matters  put  into  it,  may  appear  doubtful  to  the 
practical  dyer,  as  his  daily  experience  teaches  him  that  the 
waters  he  uses  have  a  strong  effect  upon  many  of  the  dyes, 
and  that  certain  kinds  of  water  are  better  for  some  of  his  colors 
than  others,  which  manifests  a  difference  either  in  the  condition 
or  constitution  of  the  water.  This  difference  in  water,  expe- 
rienced by  dyers,  depends  upon  foreign  matters  dissolved  in  it. 
It  would,  therefore,  be  a  great  object  for  the  dyer  to  obtain 
pure  water;  or,  if  this  is  not  practicable,  to  know  what  the 
ingredients  are  that  are  in  the  water  lie  is  using,  so  that  he  may 
either  counteract  their  effects,  and  escape  their  consequences, 
or  render  them  subservient  to  his  purpose.  The  great  practi- 
cal importance  of  water  to  the  dyer  is,  not  only  its  neutrality, 
but  also  its  solvent  power.  The  cohesion  of  solid  bodies  is 
thus  overcome,  and  the  particles  are  diffused  through  those  of 
the  water,  and  so  placed  in  the  best  possible  condition  for  com- 
bining with  the  particles  of  other  bodies  brought  into  proximity 
with  them.  We  may  illustrate  this  by  taking  two  solid  sub- 
stances that  have  a  strong  affinity  for  each  other,  say  tartaric 
acid  and  carbonate  of  soda;  mix  them  together  dry,  there  will 
be  no  apparent  action  ;  but  if  these  substances  be  previously 
dissolved  in  water,  and  mixed,  the  action  is  violent  and  imme- 
diate. As  may  be  supposed,  therefore,  it  is  its  great  solvent 
powers  that  gives  us  impure  water. 

Water  is  rendered  pure  by  distillation.  When  caused  to 
boil,  it  passes  off  as  steam,  and  when  steam  is  condensed  by 
cooling,  it  is  pure  water,  provided  the  impurities  which  were 
in  the  water  before  boiling  do  not  fly  off  at  a  lower  temperature 
than  that  of  212°.  For  instance,  gaseous  matters  are  expelled 
at  lower  temperatures,  and  alcohol,  which  boils  at  180°,  is  also 
given  off;  but  the  impurities  that  are  found  in  common  water 
to  affect  the  dyer  are  not  given  off,  except  these  be  in  the 
water  in  great  quantities,  as  in  lyes,  in  boiling  which  some  of 


52 


WATER. 


the  soda  or  potash  is  carried  away  with  the  steam,  as  already 
noticed. 

The  original  source  of  all  our  water  is  from  the  surface  of 
the  ocean  ;  it  is  evaporated  or  vaporized,  and  carried  through 
the  atmosphere  in  the  form  of  clouds,  or  in  solution,  and  de- 
posited upon  the  earth  as  dew  or  rain  ;  but  in  this  state,  it 
dissolves  matters  from  the  atmosphere,  such  as  carbonic  acid, 
ammonia,  &c. ;  so  that  rain-water,  especially  if  near  towns, 
is  not  altogether  free  of  impurities.  Nevertheless,  when  far 
from  towns,  or  after  having  fallen  for  some  time  to  purify  the 
air,  rain  is  the  purest  water  in  nature ;  but  the  moment  it 
touches  the  earth,  it  dissolves  some  solid  matters,  and  becomes 
contaminated  with  the  ingredients  of  the  soil  over  or  through 
which  it  passes;  and  these  ingredients  cause  the  differences 
experienced  by  dyers.  The  nature  of  the  impurities  depends 
upon  the  immediate  source  of  the  water,  the  nature  of  the  soil 
or  strata  of  earth  through  which  it  has  passed,  and  as  these 
substances  act  and  react  upon  the  dyestuffs  used,  it  becomes  of 
the  first  importance  that  the  dyer  should  fully  comprehend 
the  character  and  effects  of  the  substances  dissolved  in  the 
water  he  is  using.  These  ingredients  are  generally  lime,  mag- 
nesia, alumina,  potash,  soda,  iron,  cppper,  sulphuric  acid,  hydro- 
chloric acid,  and  carbonic  acid.  There  are  also  other  sub- 
stances, which  have  been  found  in  springs,  in  more  minute 
quantities,  but  which  we  need  not  enumerate  here,  as  they  are 
not  common ;  and  even  some  of  these  given,  such  as  copper, 
are  not  often  present  in  waters  used  in  the  dye  house.  These 
earthy  substances  are  generally  found  in  the  water  combined 
as  sulphates,  chlorides,  or  carbonates.  There  are  also  gases 
present  in  all  waters,  as  atmospheric  air,  carbonic  acid,  sulphu- 
rous acid,  &c.  The  last  named  gas  is  easily  detected  by  the 
smell,  and  water  could  not  be  used  for  dyeing  containing  an 
appreciable  quantity  of  it.  Copper  will  not  be  present  except 
in  the  vicinity  of  a  copper  mine,  or  a  copper-ore  vein,  which 
would  not  be  a  fitting  locality  for  a  dye-house.  Iron,  as  a  sul- 
phate, or  chloride,  is  often  present  in  very  minute  quantity; 
but  when  the  quantity  is  considerable,  the  water  is  not  good 
for  many  purposes;  and,  if  the  water  is  conveyed  through  lead 
pipes,  or  retained  in  leaden  tanks,  a  small  trace  of  lead  may  be 
detected,  which  is  not  only  deleterious  to  the  dyer's  operations, 
but  very  destructive  to  health.  One  common  definition  of  the 
quality  of  water  is  hard  and  soft;  but  this  expression,  so  far  as 
regards  the  dyer,  is  somewhat  ambiguous,  and  is  only  useful 
when  alkalies  and  soaps  are  to  be  used.  Distilled  water  is  soft 
and  pure,  and  useful  for  all  purposes  of  the  arts;  but  a  water 
may  be  soft  and  useful  for  bleaching  and  washing,  and  very 


WATER. 


53 


deleterious  in  dyeing;  and  it  may  be  hard,  and  yet  good  for 
dyeing  most  colors.  Soch  a  term,  therefore,  does  not  denote 
any  particular  kinds  of  impurities.  If  a  piece  of  pure  white 
soap  be  dissolved  in  alcohol,  not  so  strong  as  to  form  a  jelly, 
and  a  little  of  this  solution  be  dropped  into  water,  if  the  soap 
curdles  the  water  is  hard;  if  not,  it  is  soft.  If  hard,  the  ingre- 
dients are  of  an  acid  or  an  earthy  nature,  such  as  carbonic  acid, 
carbonate  of  lime  or  iron,  sulphate  of  lime,  &c. ;  if  soft  it  may 
contain  alkalies.  The  ingredients  in  the  water  are  often  so 
minute  that  the  ordinary  tests  do  not,  for  some  time,  detect 
them.  The  best  mode  of  proceeding  is  to  apply  the  soap  test 
preliminarily,  as  a  sort  of  guide;*  next,  to  try  the  water  with 
delicately-prepared  test  papers,  and  observe  whether  it  has  any 
acid  or  alkaline  reaction,  then  take  a  gallon  of  the  water  and 
boil  it  down  to  a  pint;  put  this  into  a  narrow  jar,  and  allow  it 
to  settle  for  a  few  hours  ;  pour  off  the  clear  liquid  into  another 
vessel,  and  retain  the  turbid  remainder  for  examination.  The 
insoluble  precipitate,  if  any,  will  most  probably  be  carbonate 
and  sulphate  of  lime,  and  a  little  iron.  Carbonate  of  lime  is 
held  in  solution  as  bi-carbonate ;  but  the  boiling  decomposes 
this  compound,  one  proportion  of  carbonic  acid  being  given  off, 
and  the  insoluble  carbonate  precipitates.  The  sulphate  of  lime 
is  soluble  only  in  small  quantity,  and  a  little  is  precipitated  by 
boiling.  To  the  precipitate  add  a  few  drops  of  hydrochloric 
acid,  and  the  carbonate  of  lime  and  iron  will  dissolve  with 
effervescence,  while  the  sulphate  will  remain  undissolved.  A 
drop  or  two  of  gallic  acid  added  to  the  acid  solution  will  detect 
iron,  by  giving  a  black  or  bluish  color.  A  portion  of  this 
solution  may  be  taken,  and  a  little  ammonia  added  to  neutralize 
the  acid;  if  lime  is  present,  the  addition  of  a  little  oxalate  of 
ammonia  will  give  a  white  precipitate. 

The  pint  of  water  boiled  down  is  now  divided  into  five 
different  portions,  and  put  into  small  wine  or  test  glasses. 

To  one  portion  are  added  a  few  drops  of  gallic  acid,  which,  if 
iron  be  present,  will,  after  standing  some  time,  produce  a  bluish 
color. 

To  another  portion  add  a  few  drops  of  oxalate  of  ammonia, 
which  will  give  a  white  precipitate  if  lime  is  present.  This 
should  be  heated  a  little. 

To  a  third  portion  add  a  few  drops  of  phosphate  of  soda, 
and  stir  it  well.  After  standing  some  time,  if  a  white  precipi- 
tate be  formed,  this  will  indicate  the  presence  of  magnesia. 

*  The  soap  test  for  water  lias  been  carried  out  to  a  great  extent,  and  pro- 
bably to  general  practical  use,  by  Professor  T.  Clark.  (See  his  papers  in  the 
Chemical  Gazette,) 


54 


WATER. 


To  a  fourth  portion  add  chloride  of  barium;  if  a  white  pre- 
cipitate is  obtained,  which  is  not  redissolved  by  adding  a  little 
pure  nitric  acid,  sulphuric  acid  is  present. 

To  the  fifth  portion  add  nitrate  of  silver;  if  a  white  precipi- 
tate is  formed,  not  redissolved  by  the  addition  of  a  little  pure 
nitric  acid,  then  hydrochloric  acid  is  present. 

These  tests,  and  the  nitric  acid  used,  of  course,  must  be  per- 
fectly pure,  or  no  dependence  can  be  placed  upon  the  results. 

If  carbonic  acid  exists  in  the  water,  which  it  does  very  com- 
monly in  combination  with  a  base,  it  will  be  known,  as  already 
intimated,  by  the  effervescence  caused  by  the  addition  of  an 
acid  ;  but  it  may  exist  free ;  and  the  best  way  to  detect  it,  is  to 
take  a  separate  quantity  of  the  water,  without  boiling,  say  a 
pint,  and  add  to  it  a  little  clear  lime-water ;  if  milkiness  appear, 
carbonic  acid  is  present,  either  free  or  as  bi-carbonate  of  lime. 

If  blue  litmus  paper  be  reddened,  there  is  free  acid  present 
in  the  water. 

This  manner  of  proceeding,  which  is  very  simple,  is  sufficient 
to  give  the  dyer  an  idea  of  the  impurities  he  has  to  contend 
with.  Of  course,  the  effects  of  each  of  these  separately,  or 
together,  upon  his  dye-drugs,  will  also  have  to  be  studied;  but 
this  we  refer  to  the  separate  heads  under  which  they  naturally 
fall.  Should  a  more  correct  investigation  be  required,  such  as 
the  exact  quantities  of  each  ingredient,  this  must  be  done  by  a 
regular  course  of  analysis,  which,  we  are  afraid,  few  practical 
dyers  have  the  apparatus,  or  other  means  of  making.  How- 
ever, with  the  tests  referred  to,  a  near  approximation  may  be 
come  at,  by  boiling  the  gallon  of  water  to  dryness,  and  care- 
fully weighing  the  contents,  which  will  give  the  whole  solid 
matters  in  the  gallon;  and  afterwards,  by  dissolving  this  in  dis- 
tilled water,  pouring  off  the  solution,  and  drying  the  insoluble 
portion,  the  quantity  of  soluble  salts,  which  may  be  those  of 
potash,  soda,  magnesia,  &c,  will  be  found.  The  water  is  tested 
for  these  and  all  the  other  ingredients,  by  the  tests  given.  To  the 
remaining  insoluble  part,  a  few  drops  of  hydrochloric  acid  are 
added;  and  notice  is  taken  if  this  produces  effervescence.  This 
acid  solution  is  then  diluted  with  distilled  water,  and  tested  as 
above;  if  anything  remains  insoluble,  it  is  again  dried  and 
weighed,  and  the  result  will  indicate  the  silica  present.  The 
following  table,  from  Parke's  Chemical  Essays,  a  book  well 
worth  perusal  by  practical  mens  will  be  a  guide  to  the  testing 
of  water: — 


WATER. 


55 


TEST  USED. 

Oxalates,  or  oxalic  acid. 
Litmus. 

Turmeric  paper. 
Chloride  of  platinum  in 

cohol. 
Nitrate  of  silver. 
Salts  of  barytes. 
Lime-water. 

Acetate  of  lead. 

Chloride  of  lime. 
Polished  iron. 
Phosphate  of  soda. 

For  the  particular  effects  of  some  of  these  tests,  the  reader  is 
referred  to  the  articles  upon  these  substances. 

Water  is  used  in  the  dye-house  principally  as  a  solvent ;  but 
its  solvent  property  depends  upon  certain  laws.  The  action 
being  the  mutual  attraction  between  the  solid  and  fluid;  it 
becomes  weaker  as  the  attractions  are  satisfied.  If,  for  example, 
we  take  a  piece  of  white  sugar  of  lead, t and  immerse  one  small 
point  of  it  in  water,  the  liquid  is  quickly  drawn  up  into  its 
pores,  and  adheres  to  the  particles  of  the  salt.  If  more  water 
than  is  merely  sufficient  to  wet  the  particles  is  allowed  to  enter, 
the  solid  particles  of  the  salt  break  down  and  disappear  in  the 
water ;  in  other  words,  the  salt  is  dissolved.  But  this  action  of 
the  water  upon  the  salt  is  limited;  it  is  very  powerful  at  first, 
but  the  salt  becoming  diffused  through  the  liquid,  the  action 
upon  the  solid  decreases  gradually,  until  the  water  gets  satisfied, 
and  will  dissolve  no  more;  the  water  is  then  said  to  be  satu- 
rated. 

An  important  point  in  dissolving  salts  may  here  be  noticed. 
In  dissolving  quantities  of  crystallized  salts,  such  as  alum, 
sugar  of  lead,  &c,  the  custom  is  to  put  the  solid  crystals  into 
a  vessel,  and  pour  water  upon  them ;  and  a  person  keeps  stir- 
ring until  the  whole  is  dissolved.  This  takes  up  much  valua- 
ble time,  and  there  is  often  a  remainder  of  the  salt  not  dissolved. 
If,  instead  of  proceeding  in  this  way,  the  quantity  of  water 
which  it  is  necessary  to  use  be  put  into  the  vessel,  and  the 
crystals  of  the  salt  be  suspended  upon  the  surface,  the  solution 
would  proceed  much  more  rapidly,  and  more  economically, 
than  any  other  way.  As  the  particles  of  water  take  up  the 
particles  of  the  salt,  they  become  heavier,  and  sink  ;  other  par- 
ticles take  their  place,  dissolve  more  of  the  salt,  and  sink  in 
turn  ;  so  that  the  action  of  a  constant  current  of  liquid  is  kept 


WILL  DETECT. 

Lime,  or  its  salts. 
Uncombined  acids. 
Alkalies  and  alkaline  earths. 

|  Salts  of  potash. 

Hydrochloric  acid  or  chlorides. 

Sulphuric  acid  or  sulphates. 

Carbonic  acid, 
f  Sulphuretted  hydrogen  in  be- 
\     coming  black,  or  sulphates. 

Carbonated  alkalies. 

Copper  (is  precipitated). 

Magnesia. 


56 


WATER. 


up  on  the  suspended  crystals,  and  always  of  that  portion  of  the 
liquid  most  capable  of  dissolving.  When  crystals  of  any  salt 
are  put  into  a  vessel,  and  water  poured  over  them  and  allowed 
to  remain,  they  are  a  very  long  time  in  being  dissolved  ;  as 
the  water  surrounding  the  crystals  becomes  saturated,  and 
incapable  of  dissolving  more,  and  from  its  weight  it  remains  at 
the  bottom  of  the  vessel.  This  may  be  beautifully  illustrated 
by  taking  three  tumblers  filled  with  water,  and  adding  to  each 
an  equal  weight  of  crystallized  sulphate  of  copper.  In  the  one, 
let  the  crystals  rest  at  the  bottom,  stir  the  other  constantly,  and 
let  the  third  be  suspended  upon  the  surface  of  the  water ;  the 
action  will  be  seen,  and  the  difference  in  time  appreciated. 

In  general,  hot  water  dissolves  more  of  a  salt  than  cold  wa- 
ter ;  but  the  relation  of  different  dissolving  powers  of  water,  at 
different  temperatures,  and  for  different  salts,  is  very  curious. 
Some  salts  dissolve  equally  at  all  temperatures,  such  as  com- 
mon salt.  Some  salts  dissolve  least  in  cold  water,  and  increase 
gradually  as  the  water  is  heated ;  others  again,  increase  rapidly, 
until  the  water  is  at  a  certain  temperature,  and  then  become 
less  soluble ;  while  other  substances,  such  as  lime,  dissolve 
most  easily  when  the  water  is  cold.  Thus,  66  gallons  water, 
at  32°  Fah.  dissolve  1  lb.  lime ;  but  it  will  take  75  gallons  at 
60°  Fahr.,  or  128  gallons  at  212°,  to  produce  the  same  effect ; 
so  that  boiling  water  can  contain  only  about  half  of  the  lime 
that  ice-cold  water  can.  Thus,  when  lime-water,  at  60°,  which 
is  about  the  maximum  heat  of  water  in  summer,  is  boiled,  a 
quantity  of  lime  is  deposited  as  the  heat  increases.  This  is 
often  experienced  in  the  raising  of  chrome  oranges. 

The  following  table  illustrates  these  remarks,  and  is  of  the 
greatest  value  to  the  dyer : — 


2°      50°    6S°      86°     104°     122°     140°     158°    176°    194°   212°  230° 


WATER.  5T 


v.  ■ 


It  will  be  seen  here  that  if  a  salt  is  dissolved  in  boiling  wa- 
ter to  saturation,  and  allowed  to  cool,  a  great  quantity  will  be 
deposited  either  as  crystals  or  powder;  also,  if  we  wish  to  have 
a  highly-saturated  solution,  there  are  certain  temperatures  bet- 
ter adapted  for  obtaining  it  than  others.  The  best  means  is  to 
use  the  salt  dissolved  in  cold  water,  as  above  stated ;  and  the 
dyer,  while  he  uses  his  stuff,  as  the  salts  of  iron;  alum,  &c, 
should  know  that  when  he  uses  the  full  of  a  ladle,  or  pail,  or 
small  mug,  he  is  taking  exactly  so  many  ounces  or  pounds  of 
the  salt,  not  so  many  measures,  as  is  generally  the  case,  without 
reference  to  the  particular  strength  of  the  solution. 

The  following  table  of  the  quantity  of  a  salt  dissolved  in 
a  gallon  of  cold  water  (60°  Fah.),  at  saturation  will  be  an  ex- 
ample of  this : — 

Common  salt   3.6   lb.  per  gallon. 

Sal-ammoniac   3.3  — 

Sulphate  of  copper   3.8  — 

Sulphate  of  iron   6.66  — 

Sulphate  of  zinc  (anhydrous)  .    .  5.0  — 

Sulphate  of  nickel   3.3  — 

Sulphate  of  soda  (hydrated)     .    .  3.7  — 

Alum   1.2  — 

Comparing  this  with  the  diagram  above,  it  will  be  seen  that 
double  the  quantity  of  some  of  these  salts  is  dissovled  in  boiling 
water. 

Besides  the  property  for  dissolving  solid  bodies,  which  we 
have  been  considering,  water,  as  has  been  previously  said,  has 
also  the  property  of  dissolving  gases,  and  holding  them  in 
solution.  In  this  case,  cold  water  is  a  more  powerful  solvent 
than  hot.  Some  gases,  if  held  in  solution  by  water  used  in 
dyeing,  would  be  very  deleterious;  and  as  many  of  these  gases 
are  often  floating  about  in  the  dye-house,  they  may  be  absorbed 
by  the  water  in  small  quantities,  and  be  injurious,  and  the 
cause  of  the  injury  may  not  be  known  or  thought  of.  The 
following  are  a  few  of  these  gases,  and  their  solubility  in 
water. 

100  volumes,  or  cubic  inches  of  water,  at  60°,  will  dissolve 
about — 

253  volumes  of  sulphuretted  hydrogen,  weighing  93.6  grains. 
4380       "         sulphurous  acid,  "      3000.0  " 

206       "         chlorine,  "       155.7  " 

100       "  carbonic  acid,  "         47.2  " 

76       "  nitrous  oxide,  "         75.  " 

Any  of  these  gases,  in  the  water,  will  affect  colors,  and  they 
are  all,  to  some  extent,  gases  given  off  in  the  dye-house. 


58 


NITROGEN". 


One  gallon  is  equal  to  277  cubic  inches,  so  that  each  gallon 
is  capable  of  holding  in  solution. — 

259.3  grains  of  sulphuretted  hydrogen. 
8310.   grains  of  sulphurous  acid. 
431.3  grains  of  chlorine. 
130.7  grains  of  carbonic  acid. 
207.7  grains  of  nitrous  fumes. 

Bin-oxide  of  Hydrogen. — Bin-oxide  of  hydrogen  is  a  color- 
less liquid  like  water ;  it  has  a  metallic  taste,  and  bleaches 
almost  instantly  all  organic  colored  substances.  Its  preparation 
is  difficult  and  expensive.  It  is  obtained  by  the  decomposition 
of  bin-oxide  of  barium;  the  preparation  of  which  is  also  difficult. 
There  are  so  many  minute  precautions  required  for  the  prepara- 
tion of  the  bin-oxide  of  hydrogen,  that  almost  no  description 
which  our  limits  permit  would  enable  the  student  to  prepare 
it ;  these  are  all  given  in  detail,  by  Thenard,  the  discoverer  of 
the  compound,  in  his  Traite  de  Qhimie  (vol.  i.,  6th  edition). 

Could  there  be  any  means  of  procuring  it  readily  and  cheap, 
its  uses  would  be  invaluable,  both  as  a  bleaching  agent  and  also 
for  oxidizing,  and  many  other  operations  in  the  arts.  It  is 
often  referred  to  in  proof  that  oxygen  has  bleaching  properties 
as  well  as  chlorine,  a  fact  which  will  be  noticed  to  some  extent 
under  that  element. 

Hydrogen  combines  with  other  elements  besides  oxygen, 
giving  rise  to  important  compounds,  such  as  sulphuretted  hy- 
drogen, a  gas  we  have  just  referred  to,  and  others  which  will  be 
treated  of  under  the  separate  elements  with  which  it  combines. 

Nitrogen  (N.  14). 

If  a  small  vessel  be  floated  upon  water,  with  a  piece  of  phos- 
phorus in  it,  and  this  be  set  on  fire,  and  a  glass  jar  be  inverted 

over  it,  as  represented  by  the  annexed 
Fig  4.  figure,  the  flame  is  soon  extinguished, 

and  the  water,  when  the  air  within 
the  glass  cools,  rises  into  the  jar.  Let 
the  whole  stand  until  the  white  fumes 
in  the  glass  disappear,  the  remaining 
air  in  the  jar  will  be  found  to  differ 
entirely  from  common  air;  a  candle 
will  not  burn  in  it,  and  an  animal  put 
into  it  would  very  soon  die.  This 
gaseous  substance  is  nitrogen.  The 
atmosphere*  is  composed  of  oxygen 
and  nitrogen  ;  and  the  burning  phosphorus  combines  with  the 
former  of  these  gases,  forming  phosphorous  acid,  constituting 


NITROGEN". 


59 


the  white  cloud  referred  to,  which  is  absorbed  by  the  water 
after  a  little  time.  The  rising  up  of  the  water  into  the  jar  is  to 
supply  the  place  occupied  by  the  oxygen  consumed,  and  nothing 
but  nitrogen  remains. 

This  element  was  first  called  Azote — the  life-destroyer — 
by  its  discoverer,  Dr.  Rutherford,  from  its  not  having  the 
power  of  supporting  life ;  but  the  name  was  afterwards  changed 
to  nitrogen,  on  account  of  its  being  found  to  be  the  basic  con- 
stituent of  nitric  acid  (aqua-fortis).  Nitrogen  has  neither  taste 
nor  smell,  and  is  rather  lighter  than  oxygen.  Its  use  in  the 
atmosphere  is  supposed  to  be  for  diluting  the  oxygen  ;  but  there 
is  ,no  doubt  that  other  important  purposes  are  served  by  its 
presence  in  the  air,  although  we  may  be  ignorant  of  them,  as 
it  forms  an  essential  constituent  of  animals  and  vegetables,  and 
also  of  many  mineral  productions.  Nitrogen  is  peculiar  for 
what  are  termed  inert  or  negative  properties.  We  cannot  cause 
it  to  combine  directly  with  any  other  element,  as  we  do  oxygen 
and  hydrogen,  or  hydrogen  and  chlorine;  nevertheless,  it  com- 
bines with  a  number  of  elements,  when  their  compounds  are 
being  decomposed. 

With  oxygen,  nitrogen  forms  a  variety  of  interesting  com- 
pounds, already  alluded  to  (page  38),  but  which  we  will  here 
notice  more  in  detail,  particularly  those  more  commonly  met 
with.  As  already  remarked,  the  atmosphere  is  a  mixture  of 
nitrogen  and  oxygen,  found  to  be  in  very  nearly  the  same  pro- 
portions under  all  circumstances  and  at  all  places,  not  in  chemi- 
cal union,  but  maintained  in  equal  mixture  by  the  principle  of 
diffusion.  There  are  a  variety  of  methods  for  ascertaining  the 
proportions  of  oxygen  and  nitrogen  in  the  air;  the  one  just 
described,  the  burning  of  phosphorus  in  an  inverted  jar  over 
water,  will  suffice  as  an  example.  The  results  of  careful  inves- 
tigations into  this  subject  give  as  the  constitution  of  the  atmos- 
phere in  100  parts : — 

21  Oxygen. 
79  Nitrogen. 

But,  from  the  constant  evaporation  of  water  from  the  sea  and 
surface  of  the  earth,  and  the  production,  by  many  causes,  of 
carbonic  acid  gas,  which  finds  its  way  into  the  atmosphere,  the 
air  always  contains  a  small  portion  of  those  ingredients,  which 
being  taken  into  account,  makes  the  composition  : — 

Oxygen  '   20. 

Nitrogen   79. 

Vapor  of  water  .....  0.9. 
Carbonic  acid  0.1. 


100.0 


60 


BINOXIDE  OF  NITROGEN". 


The  dyer  cannot  fail  to  have  observed  a  thin  crust  of  solid 
matter  upon  the  surface  of  his  lime  solution,  bleaching  liquor, 
and  blue  vats.  This  crust  is  the  carbonate  of  lime,  and  is 
caused  by  the  carbonic  acid  in  the  air  combining  with  the  lime, 
and  forming  an  insoluble  carbonate.  The  presence  of  this  gas 
in  the  air  has  no  deleterious  effects  in  the  dye-house,  so  far  as 
we  know,  except  its  combining  with  caustic  alkalies,  if  exposed, 
and  deteriorating  them. 

The  oxygen  of  the  atmosphere  plays  a  very  prominent  part 
in  the  dye-house,  and  the  knowledge  of  the  true  constitution  of 
the  air  will  make  many  of  these  phenomena  better  understood. 
This  gas  not  being  in  chemical  union  with  the  nitrogen,  there 
is  no  chemical  force  retaining  and  preventing  it  from  acting 
upon  other  bodies,  when  brought  under  its  influence. 

The  principal  compounds  formed  between  nitrogen  and 
oxygen  are : — 

Protoxide  of  nitrogen     ....  NO. 

Deutoxide  of  nitrogen    ....  N02. 

Nitrous  acid  ......  N03. 

Peroxide  of  nitrogen      ....  N04. 

Nitric  acid     ......  N05. 

Some  of  these  being  of  no  known  importance  in  the  dye- 
house,  we  need  do  little  more  than  refer  to  the  condition  in 
which  they  may  be  found. 

Protoxide  of  Nitrogen*  is  a  gaseous  body,  and  is  easily 
obtained  by  distilling  nitrate  of  ammonia  in  a  retort  as  described 
for  obtaining  oxygen  (page  48),  and  collecing  the  gas  as  it 
escapes  over  water.  It  is  known  under  the  appellation  of 
laughing  gas. 

Binoxide  of  Nitrogen  is  also  a  gaseous  body,  and  is  evolved 
when  metals  are  being  dissolved  in  nitric  acid.  When  dissolv- 
ing iron  or  copper  in  nitric  acid,  in  open  vessels,  as  is  done  for 
the  preparation  of  mordants,  a  dense  red  gas  is  seen  to  escape 
during  the  process.  This  red  gas  is  produced  by  the  binoxide 
of  nitrogen  combining  with  the  oxygen  in  the  atmosphere, 
and  forming  a  peroxide;  but  when  the  metal  is  dissolved  in  a 
retort,  or  other  close  vessel,  as  described  for  hydrogen,  and  the 
gas  collected  in*a  glass  jar,  it  is  found  perfectly  colorless.  The 
following*  is  the  reaction  which  takes  place  when  a  metal  is 
being  dissolved  in  nitric  acid  and  oxide  of  nitrogen  envolved. 
Every  three  proportions  of  metal  require  four  proportions  of 
acid,  one  of  which  is  decomposed  according  to  the  following 
formula,  supposing  copper  to  be  the  metal  dissolved : — 
3Cu  +  4N05  =  3Cu  0  N05  +  N02. 


NITRIC  ACID. 


61 


But,  according  to  the  theory  of  salt  radicals  (page  45),  the  reac- 
tion is  the  following: — 

3Cu  +  4N06H  =  3Cu  N06  +  4HO,  N02. 

According  to  either  view  of  the  reactions  which  take  place, 
it  will  be  observed  that  the  proportions  are  the  same,  which 
may  enable  the  dyer  to  guide  himself  in  these  substances  when 
making  nitrates  of  iron  or  copper. 

Nitrous  Acid. — This  acid  is  prepared  by  taking  four 
volumes  of  the  binoxide  of  nitrogen,  adding  to  them  one 
volume  of  oxygen,  and  exposing  this  mixture  to  a  low  degree 
of  Qold  ;  the  gases,  under  these  circumstances,  unite,  and  form  a 
greenish-colored  liquid,  which  is  nitrous  acid.  As  may  be 
supposed,  from  the  manner  in  which  it  is  prepared,  this  sub- 
stance is  very  volatile.  If  thrown  into  water  it  is  decomposed. 
But  it  can  be  obtained  by  several  means,  in  combination  with 
bases,  such  as  potash,  soda,  lead,  &c,  with  which  it  is  more 
stable. 

Peroxide  of  Nitrogen. — This  compound  is  formed  when 
the  binoxide  of  nitrogen  is  allowed  to  escape  into  the  atmo- 
sphere, and  constitutes  the  red  fumes  observed  when  dissolving 
iron  or  copper  in  nitric  acid.  It  is  also  obtained  by  distilling 
nitrate  of  lead  in  a  retort,  and  allowing  the  fumes  to  pass  into 
a  bottle  or  flask  kept  cool  by  placing  it  in  a  freezing  mixture, 
such  as  snow  and  salt.  It  condenses  in  this  vessel* and  forms 
a  reddish-yellow  liquid,  which,  however,  passes  off'  as  gaseous 
fumes,  by  the  slightest  elevation  of  temperature.  These  fumes 
are  very  corrosive:  they  are  fatal  to  animal  and  vegetable  life, 
and  rapidly  destroy  all  colors,  and  also  the  fibres  of  the  cloth 
or  yarn  exposed  to  their  action.  The  dissolving  of  metals  in 
nitric  acid  should,  therefore,  never  be  carried  on  within  or  near 
the  dye-house,  or  any  place  where  goods  are  exposed.  We 
have  seen  a  little  inattention  to  these  precautions  destroy  the 
labor  of  several  days,  and  this,  too,  wrhen  the  destructive  agent 
was  hardly  perceptible  to  the  senses,  although  its  odor  is 
amongst  the  most  easily  detected  of  gaseous  compounds.  This 
gas  is  also  very  suffocating  and  hurtful  to  health,  and  care 
should  be  taken  that  it  is  not  breathed.  It  is  its  presence  in 
nitric  acid  which  gives  that  acid  the  reddish-brown  color  which 
the  aqua-fortis  of  commerce  often  has. 

Nitric  Acid. — This  acid  exists  abundantly  in  nature,  in  com- 
bination with  other  substances  forming  nitrates.  We  have 
said  before  that  nitrogen  and  oxygen  do  not  combine  directly 
in  the  same  manner  as  oxygen  and  hydrogen.  There  is  no 
doubt,  however,  that  the  nitric  acid  which  is  found  united  with 
bases  in  nature,  has  been  the  result  of  the  union  of  the  oxygen 


62 


NITRIC  ACID. 


and  nitrogen  of  tbe  atmosphere.  When  a  quantity  of  hydrogen 
is  mixed  with  nitrogen  in  an  open  vessel,  and  ignited,  it  burns 
rapidly  in  contact  with  the  oxygen  of  the  air,  forming  water ; 
and  the  water  thus  formed  is  found  to  contain  nitric  acid.  If 
electric  sparks  be  passed  through  air,  confined  in  a  vessel  above 
a  solution  of  an  alkali,  a  portion  of  the  alkali  is  converted  into 
a  nitrate.  Eain  which  falls  during  a  thunderstorm,  almost 
always  contains  nitrate  of  ammonia.  Ammonia  is  always  being 
given  into  the  air  by  the  decomposition  of  animal  and  vegetable 
substances,  and  absorbed  by  the  watery  vapor ;  so  that  when 
electric  currents  pass  through  the  air  during  a  thunderstorm, 
the  nitric  acid  formed  combines  with  this  ammonia,  forming 
a  nitrate.  In  warm  climates,  where  electric  currents  are 
abundant,  the  quantity  of  ammonia  in  the  air  is  considerable ; 
the  formation  of  nitrate  of  ammonia  is,  therefore,  proportionably 
great;  and  this,  being  washed  down  by  the  rain  into  porous 
limestone  soils,  is  decomposed  by  the  nitric  acid  combining 
with  the  lime  and  also  with  potash  and  soda,  which  are  general 
constituents  of  soils,  forming  nitrates  with  these  bases,  and  the 
ammonia  is  accordingly  liberated,  either  to  be  given  to  the  air 
again,  or  taken  up  by  plants,  as  a  constituent  of  their  food.  In 
this  way,  immense  beds  of  nitrates  have  been  formed  in  the 
East  Indies  and  in  South  America.  In  Chili  and  Peru,  there 
are  found  large  deposits  of  nitrate  of  soda  upon  the  surface  of 
the  soil.  Great  quantities  of  nitrate  of  potash  and  soda  are 
imported  from  these  localities  for  the  various  manufacturing 
purposes  of  this  country,  where  they  are  now  extensively 
applied.  The  nitrate  of  lime  and  other  earths,  are  converted 
into  nitrate  of  potash,  by  mixing  them  with  carbonate  of  potash, 
before  sending  them  to  this  country. 

Nitric  acid  is  prepared  from  the  nitrate  of  potash  or  soda, 
by  decomposing  it  with  sulphuric  acid.  This  may  be  done,  on 
a  small  scale,  by  putting  a  little  of  any  of  these  salts  into  a 
retort,  adding  some  sulphuric  acid,  and  then  applying  heat. 
The  beak  of  the  retort  is  inserted  into  a  receiver,  which  must 
be  kept  cool  by  causing  cold  water  to  drop  upon  it.  The 
arrangement  of  the  apparatus  is  indicated  by  the  annexed 
figure. 

At  the  beginning  of  this  experiment,  red  fumes  of  peroxide 
of  nitrogen  come  off;  but  soon  after  a  colorless  liquid  is  seen  to 
distil  over,  and  drop  into  the  receiver — this  is  nitric  acid.  The 
reaction  which  takes  place  may  be  represented  by  the  following 
formula : — 

Na  N06  +  S04H  -  Na  S04  +  N06H. 

Nitrate  of  soda  is  now  more  generally  used  than  potash, 
being  cheaper,  and  having  a  lower  combining  equivalent,  more 


NITRIC  ACID. 


63 


nitric  acid  is  obtained  from  a  given  weight.  Thus,  100  lbs.  of 
nitrate  of  potash  give  62  lbs.  of  acid;  while  100  lbs.  of  nitrate 

Fig.  5. 


of  soda  would  give  74  lbs.  The  best  proportion  of  sulphuric 
acid  to  use  with  nitrate  of  potash  is  2  equivalents,  whereas  less 
suffices  with  nitrate  of  soda. 

Nitric  acid  is  generally  prepared,  on  the  large  scale,  in  iron 
cylinders,  placed  so  that  a  fire  plays  round  them.  Into  these 
cylinders  are  put  the  materials;  and  the  acid  vapors  which  are 
distilled  over  are  conveyed  to  the  condensing  apparatus  by 
glazed  earthenware  pipes. 

The  nitric  acid  of  commerce  has  generally  a  light-brown  co- 
lor, caused,  as  before  stated  (p.  61),  by  having  a  little  peroxide 
of  nitrogen  in  it.  Sir  H.  Davy  drew  out  the  following  table  of 
proportions  of  nitrous  gas  contained  in  this  acid,  from  its 
shades  of  color.    Thus,  in.  100  parts — 

Peroxide  of 

Color. 

A  pale  yellow  has  . 
A' bright  yellow  has 
A  dark  orange  has 
A  light  olive  has 
A  dark  olive  has 
A  bright  green  has 
A  blue  green  tras 

This  table  must  be  considered  to  refer  only  to  strong  acid, 
for  the  color  is  changed  by  dilution.  Thus,  when  water  is 
added  to  the  dark  orange-colored  acid,  it  changes  it  to  a  green- 
ish-yellow. 

Exposure  to  the  sun's  light  produces  change  of  color,  by  de- 
composing the  acid,  and  liberating  peroxide  of  nitrogen,  which 
remains  dissolved  in  the  acid.  A  little  oxygen  gas  is,  at  the 
same  time,  evolved  ;  and,  if  the  bottle  is  stoppered,  will  either 
drive  it  out  or  burst  the  bottle,  a  fact  too  often  experienced. 


Real  Acid. 

Water. 

Nitrogen 

.  90.5 

8.3 

1.2 

.  88.9 

8.1 

.2.9 

.  86.8 

7.6 

5.5 

.  86. 

7.5 

6.4 

.  85  4 

7.5 

7.4 

.  84.8 

7.4 

7.7 

.  84.6 

7.4 

8. 

61 


NITRIC  ACID. 


The  great  effect  of  light  upon  this  acid  may  be  tried  by  placing 
a  little  of  the  colorless  acid  in  the  rays  of  the  sun,  and  observing 
the  change  that  follows  ;  this  will  show  the  propriety  of  keep- 
ing nitric  acid  always  in  the  dark.  Neither  should  it  be 
exposed  to  the  a  ir,  by  leaving  the  stoppers  out  of  the  bottles  or 
carboys,  as  it  thereby  loses  it  strength  rapidly. 

The  nitric  acid,  formed  as  we  described,  is  often  contaminated 
with  iron,  from  the  retorts,  and  also  with  sulphuric  and  hydro- 
chloric acids,  from  a  little  common  salt  and  other  impurities 
being  in  the  nitre  used.  It  is  purified  from  these  matters  by 
redistilling  in  glass  retorts.  The  acid  coming  off'  first  in  the 
distillation  contains  some  hydrochloric  acid  ;  then  nothing  but 
pure  nitric  acid  passes  over,  until  nearly  three-fourths  of  this 
acid  is  distilled.  But  if  the  operation  be  pushed  farther,  there 
is  danger  of  impurities  passing  over.  Of  course,  what  remains 
in  the  retort  contains  the  impurities. 

Sometimes  the  quantity  of  impurities  in  the  nitric  acid  of 
commerce  is  very  considerable,  and  very  deleterious  to  the 
dyer.  The  general  test  applied  to  this  acid  in  the  dye-house 
is  the  specific  gravity,  taken  by  Twaddell's  hydrometer ;  but 
density  is  often  given  to  the  acid  by  dissolving  a  little  nitre  in 
it,  or  adding  sulphuric  acid.  We  have  seen  nitric  acid,  with 
8  per  cent,  of  sulphuric  acid,  giving  it  a  high  specific  gravity. 
We  have  also  seen  it  with  as  much  as  five  percent,  hydrochloric 
acid.  The  presence  of  either  of  these  acids  is  disadvantageous 
for  the  preparation  of  many  of  the  mordants,  as  will  be  noticed 
under  the  proper  heads. 

When  nitric  acid  contains  ?ittre,  or  any  other  salt  dissolved 
in  it,  the  impurity  may  easily  be  detected  by  evaporating  to 
dryness  a  little  of  the  acid,  either  upon  a  piece  of  glass  or  a 
porcelain  plate ;  when  the  acid  is  pure  no  residue  is  left. 

The  presence  of  sulphuric  acid  is  detected  by  diluting  a  small 
portion  of  the  acid  with  four  or  five  times  its  volume  of 
distilled  water,  and  adding  a  little  solution  of  nitrate  of 
barytes,  which  will  give  a  white  precipitate  if  sulphuric  acid  is 
present. 

Hydrochloric  acid,  or  chlorine,  may  be  detected  by  adding  a 
little  nitrate  of  silver  to  the  dilute  acid,  which  will  also  give  a 
white  precipitate  if  any  hydrochloric  acid  be  present. 

Iron  is  detected  by  adding  a  little  gall  water  to  the  dilute 
acid,  a  bluish-black  color  then  appears.  Or,  if  on  evaporating 
a  small  portion  of  the  acicl,  there  is  a  residue  of  a  brown  color, 
it  indicates  the  presence  of  iron. 

After  having  tested  for  the  presence  of  these  substances,  and 
finding  the  acid  pure,  or  nearly  so,  then  the  specific  gravity 
may  be  taken,  as  a  farther  certainty  of  the  value  of  the  acid. 


NITRIC  ACID. 


65 


This  varies  much  with  the  acids  of  commerce,  but  is  generally 
about  1.300=60°  Twaddell,  although  it  may  be  made  as  high 
as  1.500=100°  Twaddell.  Nearly  all  the  hydrometers  used 
in  this  country  are  those  known  as  Twaddell's,  which  is  an  ar- 
bitrary scale.  The  true  specific  gravity  may  be  reduced  to 
Twaddell's,  by  dividing  the  fractional  figures  by  5,  as  will  be 
observed  from  the  above.  But  in  trying  the  acids  by  a 
Twaddell's  hydrometer,  the  above  rule  is  to  be  reversed  ;  we 
then  multiply  the  degree  of  Twaddell  by  5,  add  1000,  and 
divide  the  sum  by  1000.  Thus  supposing  the  specific  gravity 
to  be  60°  of  Twaddell,  then  60  X  5=300  ;  which,  increased  bv 
100Q,  becomes  1300;  and  this,  divided  by  1000,  gives  1.300, 
the  true  specific  gravity.    Or  say  64°  Twad.,  which  is  a  com- 

,  (64  x  5)  +  1000     1320     1  Qon  .fl 

mon   number,  then  ^  J-  =  =  1.320  specific 

1000  1000  F 

gravity.    The  following  table  shows  the  quantity  of  acid  in  100 

parts,  which  may  be  called  ounces  or  pounds  or  any  weight 

convenient,  according  to  the  true  specific  gravity  : — 


TABLE  OF  THE  QUANTITY  OF  ACIDS  IN  100  PARTS  BY  WEIGHT. 


Specific  gravity. 

Acid  in  100  parts. 

Specific  gravity. 

Acid  in 

1.5000  . 

.    .  100 

1.4189  . 

.    .  75 

1.4980  . 

.    .    99  ■ 

1.4147  . 

.    .  74 

1.4960  . 

.   .  98 

1.4107  . 

.    .  73 

1.4940  . 

.    .  97 

1.4065  . 

.    .  72 

1.4910  . 

.   .  96 

1.4023  . 

.   .  71 

1.4880  . 

.    .  95 

1.3978  . 

.    .  70 

1.4850  . 

.    .  94 

1.3945  . 

.    .  69 

1.4820  . 

.    .  93 

1.3882  . 

.    .  68 

1.4790  . 

.    .  92 

1.3833  . 

.    .  67 

1.4760  . 

.    .  91 

1.3783  . 

.    .  66 

1.4730  . 

.   .  90 

1.3732  . 

.  65 

1.4700  . 

.   .  89 

1.3681  . 

.  64 

1.4670  . 

.    .  88 

1.3630    .  . 

.  63 

1.4640  . 

.    .  87 

1.3579    .  . 

.  62 

1.4600  . 

.   .  86 

1.3529    .  . 

.  61 

1.4570  . 

.   .  85 

1.3477    .  . 

.  60 

1.4530  . 

.    .  84 

1.3427    .  . 

.  59 

1.4500  . 

.    .  83 

1.3376    .  . 

.  58 

1.4460  . 

.    .  82 

1.3323    .  . 

.  57 

1.4424  . 

.    .  81 

1.3270    .  . 

.  56 

1.4385  . 

.    .  80 

1.3216    .  . 

.  55 

1.4346  . 

.    .  79 

1.3163    .  . 

.  54 

1.4306  . 

.    .  78 

1.3110    .  . 

.  53 

1.4269  . 

.   .  77 

1.3056    .  . 

.  -  52 

1.4228  . 

.    .  76 

1.3001    .  . 

.  51 

66 


NITRIC  ACID. 


Specific  gravity. 

Acid  in  100  parts. 

Specific  gravity. 

Acid  in  100  parts. 

1.2947  . 

.    .  50 

1.1403  . 

.    .  25 

1.2887  . 

.    .  49 

1.1345  . 

.    .  24 

1.2826  . 

.    .  48 

1.1286  . 

.    .  23 

1.2765  . 

.    .  47 

1.1227  . 

.    .  22 

1.2705  . 

.    .  46 

1.1168  . 

.    .  21 

1.2644  . 

.    .  45 

1.1109  . 

.    .  20 

1.2583  . 

.   .  44 

1.1051  . 

.    .  19 

1.2523  . 

.   .  43 

1.0993  . 

.    .  18 

1.2462  . 

.    .  42 

1.0935  . 

.   .  17 

1.2402  . 

.    .  41 

1.0878  . 

.    .  16 

1.2341  . 

.    .  40 

1.0821  . 

.    .  15 

1.2277  . 

.    .  39 

1.0764  . 

.    .  14 

1.2212  . 

.   .  38 

1.0708  . 

.    .  13 

1.2148  . 

.   .  37 

1.0651  . 

.    .  12 

1.2084  . 

.    .  36 

1.0595  . 

.    .  11 

1.2019  . 

.   .  35 

1.0540  . 

.    .  10 

1.1958  . 

.   .  34 

1.0485  . 

.    .  9 

1.1895  . 

.    .  33 

1.0430  . 

.    .  8 

1.1833  . 

.    .  32 

1.0375  . 

.   .  7 

1.1770  . 

.    .  31 

1.0322  . 

.    .  6 

1.1709  . 

.   .  30 

1.0267  . 

.    .  5 

1.1648  . 

.   .  29 

1.0212  . 

.    .  4 

1.1587  . 

.    .  28 

1.0159  . 

.   .  3 

1.1526  . 

.    .  27 

1.0106  . 

.    .  2 

1.1465  . 

.   .  26 

1.0053  . 

..  .  1 

The  presence  of  free  nitric  acid  in  a  solution  is  easily  ascer- 
tained by  the  production  of  red  fumes  when  a  metal  is  put 
into  it,  such  as  iron  or  copper  ;  or  by  adding  to  the  substance 
supposed  to  contain  it  a  drop  of  sulphate  of  indigo,  and  heat- 
ing the  solution  to  the  temperature  of  boiling;  the  indigo  will 
be  discolored  if  nitric  acid  is  present.  But  if  the  acid  is  com- 
bined with  a  base,  such  as  soda  or  potash,  this  test  will  not 
answer.  In  that  case  the  best  mode  of  proceeding  is  to  put 
a  little  sulphuric  acid  into  the  liquid  suspected,  and  then  to 
add  a  crystal  of  sulphate  of  iron  (copperas).  If  nitric  acid 
be  present,  a  ring  of  an  olive-brown  colored  liquid  will  form 
around  the  crystal  as  it  dissolves ;  and  by  applying  heat,  the 
well-known  smell  of  nitrous  fumes  is  felt.  By  these  simple 
means,  the  dyer  can  easily  ascertain  if  nitric  acid  is  present, 
either  free  or  combined,  in  any  compound  with  which  he  is 
working.  The  action  of  nitric  acid  on  the  different  metals  will 
be  noticed  under  the  proper  heads ;  but  one  remarkable  cir- 
cumstance connected  with  this  class  of  action  must  have  been 
observed  by  most  dyers  when  dissolving  iron,  namely,  that  on 


AMMONIA. 


67 


putting  the  iron  into  the  acid,  it  often  remains  without  any  ac- 
tion ;  when  this  occurs  with  new  acid,  complaints  are  made  that 
the  acid  is  bad  or  weak,  or  that  something  is  wrong  that  pre- 
vents it  dissolving  the  iron  ;  and  not  unfrequently  have  we 
seen  carboys  of  acid  returned  on  this  account.  Recently,  we 
had  a  sample  of  such  acid,  and  found  it  to  stand  in  specific  grav- 
ity 1.425 ;  and  to  contain  a  mere  trace  of  salts  and  sulphuric 
acid,  with  0.1  per  cent,  of  hydrochloric  acid.  It  was  a  strong 
and  comparatively  pure  nitric  acid,  which  was  its  fault.  The 
cause  of  the  iron  not  being  acted  upon,  is  from  a  condition 
which  iron  is  known  to  assume,  termed  the  passive  state;  in 
which  condition  acids  do  not  act  upon  it.  Strong  and  pure 
nitric  acid  places  the  iron  in  this  state,  and  therefore  it  is  not 
dissolved  till  the  acid  is  diluted,  or  heat  applied.  We  cite  the 
above  case  as  an  illustration  of  the  value  a  little  attention  to 
chemical  principles  would  be  in  many  dye-houses,  not  only  in 
saving  money,  but  also  preventing  the  manufacturer  being 
necessitated  either  to  adulterate  or  dilute  his  acid,  in  order  to 
preserve  a  good  and  profitable  customer. 

Nitric  acid  is  very  corrosive,  from  which  property  it  was 
named  aquafortis.  It  destroys  all  organic  bodies,  both  vege- 
table and  animal.  It  converts  vegetable  matter  into  oxalic, 
carbonic,  and  several  other  acids.  Animal  substances  are 
acted  upon  by  this  acid,  producing  the  yellow-colored  com- 
pounds, observed  when  it  comes  in  contact  with  the  skin  or 
nails.    It  should  be  used  at  all  times  with  great  care. 

Ammonia. — Nitrogen  combines  with  hydrogen,  and  forms 
a  very  important  compound,  ammonia;  composed  of  one  pro- 
portion of  nitrogen  and  three  hydrogen,  NH3.  Ammonia  is 
abundantly  obtained  from  the  destructive  distillation  of  organic 
matters  containing  nitrogen,  such  as  bones,  horns,  skins,  blood, 
and  other  animal  matters.  It  is  also  obtained  as  a  product  in 
the  gas-works.  When  animal  matters  are  decomposed  by 
burning  or  putrefaction,  ammonia  is  formed,  and  produces  the 
disagreeable  smell  which  these  operations  generally  give. 

The  ammoniacal  liquors  obtained  from  gas-works,  or  by  dis- 
tilling animal  matters,  are  saturated  with  hydrochloric  acid 
which  converts  the  ammonia  into  hydrochlorate  of  ammonia, 
(sal-ammoniac),  which  crystallizes  in  a  very  impure  state.  These 
crystals  are  collected  and  put  into  iron  pots,  set  in  a  furnace 
lined  with  fire-tiles,  and  having  a  large  cover  or  head  of  lead 
fitted  to  them.  Fire  is  applied  to  the  pots,  the  sal-ammoniac 
sublimes  and  collects  as  a  crust  upon  the  leaden  top,  from 
which  it  is  removed  from  time  to  time. 

Ammonia  is  prepared  by  mixing  equal  parts  of  slaked  lime 
and  sal-ammoniac,  and  applying  heat.   The  lime  combines  with 


68 


CHLORINE. 


the  hydrochloric  acid,  and  the  ammonia  passes  off' as  a  gas,  and 
is  conducted  by  a  pipe  into  water,  with  which  it  combines,  and 
forms  liquid  ammonia. 

Ammonia,  long  known  as  hartshorn,  is  a  strong  alkali,  and 
has  a  very  pungent,  sharp  smell.  It  is  an  exceedingly  valuable 
reagent  in  the  laboratory,  both  as  a  test  and  for  making  many 
interesting  salts  by  combination  with  acids,  the  greater  number 
of  which  are  volatile.  These  salts  are,  however,  not  much  used 
in  the  dye-house.  Ammonia  is  sometimes  used  for  the  prepa- 
ration of  archil,  for  bringing  out  the  color.  Its  action  upon  the 
coloring  matter  of  the  woods  is  very  powerful.  It  is  the 
presence  of  ammonia  and  some  of  its  salts  in  urine,  which  gives 
that  fluid  the  peculiar  properties  for  which  it  is  used  in  the  dye- 
house — as  a  cleansing  agent  for  woollen,  and  for  raising  the 
color  of  a  decoction  of  logwood. 

Nitrogen  also  combines  with  some  of  the  other  elements, 
forming  compounds  more  or  less  interesting  according  to  their 
applications,  some  of  which  will  be  noticed  when  treating  of 
the  elements  with  which  these  combinations  take  place. 

Chlorine  (CI  35.5). 

Chlorine  was  discovered  by  Scheele,  in  1774,  and  was  called 
by  him  dephlogisticated  muriatic  acid.  About  eleven  years  after 
this,  Berthollet  considered  that  he  had  found  it  to  be  a  com- 
pound of  muriatic  acid  with  oxygen,  and  hence  termed  it 
oxygenized  muriatic  acid — a  name  which  was  afterwards  con- 
tracted into  oxymuriatic  acid.  In  1811,*  Sir  H.  Davy  discovered 
it  to  be  a  simple  or  elementary  substance,  and  gave  it  the  name 
of  chlorine,  from  its  having  a  greenish-yellow  color.  Chlorine 
has  a  very  strong,  suffocating  smell,  occasions  violent  coughing 
and  debility,  and  gives  an  astringency  to  the  mouth ;  therefore 
breathing  it  ought  to  be  avoided  as  much  as  possible. 

Chlorine  exists  in  nature  in  large  quantities,  in  combination 
with  other  elements,  particularly  sodium,  forming  chloride  of 
sodium  (common  salt).  It  is  from  this 'source  that  it  is  pre- 
pared for  use  in  the  arts.  If  we  mix  about  3  parts  of  salt  with 
2  parts  of  black  oxide  of  manganese,  and  add  to  this  about  3 
parts  of  sulphuric  acid,  a  portion  of  the  oxygen  of  the  manga- 
nese combines  with  the  sodium,  and  the  chlorine  is  set  at  liberty. 
The  action  may  be  thus  defined  :— 

*  In  1809,  by  Gay  Lussac  and  Thenard. — Ed. 


HYPOCHLOEIC  ACID. 


69 


Ci  Na,  Mn  02,  2S04H=S04  Mn,  S04NA,  2HO,  CI. 

<n  a  (Chi    Chlorine  Gas. 

Common  Salt,  jgodium 

Peroxide  \  ^n.;.;..  \  Water 

Manganese,      |Q  Water. 

2  proportions       !  S04  \  Sulphate  Soda. 

Salphurie  Acid,  j  H  '  \ 

[  S04   A  Sulphate  Manganese. 

Chlorine  combines  with  almost  all  the  elements,  and  forms 
with  >thern  a  series  of  compounds  as  numerous  as  they  are 
important.  Its  power  of  combining  with,  and  decomposing, 
coloring  substances  is  remarkable,  and  has  given  it  a  promi- 
nent standing  in  the  arts.  It  combines  with  oxygen  in  various 
proportions,  giving  origin  to  several  compounds,  both  useful 
and  interesting  to  the  dyer.  These,  as  the  following  list  shows, 
have  all  acid  properties : — 

Hypochlorous  acid    .       .       .       .  CI  0. 

Hypochloric  acid      .       .       .       .  CI  04. 

Chloric  acid   CI  05. 

Hyperchloric  acid     .       .       .       .  CI  07. 

Hypochlorous  Acid. — This  is  a  very  unstable  compound, 
supposed  to  be  connected  with  many  of  the  operations  of  bleach- 
ing. It  may  be  prepared  by  diffusing  some  red  oxide  of 
mercury  in  a  little  water,  and  then  introducing  it  into  a  bottle 
previously  filled  with  chlorine  gas.  The  chlorine  is  rapidly 
absorbed,  and  combines  with  both  the  mercury  and  oxygen. 
It  produces,  with  the  former,  an  insoluble  oxychloride,  and 
with  the  latter  it  forms  hypochlorous  acid,  which  is  in  solution 
in  the  water.  This  solution  has  a  yellow  color,  smells  like 
chlorine,  and  bleaches  powerfully ;  but  it  cannot  be  kept  for 
any  length  of  time,  even  in  the  cold,  but  passes  into  chloric 
acid.  Hypochlorous  acid  combines  with  alkaline  bases,  and 
forms  hypochlorites,  which  also  possess  bleaching  powers.  It 
is  generally  supposed  that  when  chlorine  gas  is  passed  through 
solutions  of  the  alkalies,  such  as  potash  and  soda,  a  similar 
decomposition  takes  place  as  that  described  of  the  oxide  of 
mercury,  and  that  hypochlorite  of  the  alkali  is  the  bleaching 
salt  formed.    This  salt  is  decomposed  by  heat. 

Hypochloric  Acid  may  be  prepared  by  adding  strong  sul- 
phuric acid  to  chlorate  of  potash.  The  process  is  a  dangerous 
one,  and  we  would  not  advise  any  student  to  try  it,  especially  as 
neither  the  acid  nor  its  salts  are  of  any  great  importance.  The 
acid  is  a  gaseous  body  of  a  yellow  color;  it  combines  with  bases, 


70 


HYDROCHLORIC  ACID. 


and  forms  salts  termed  hypochlorates.    These  also  possess 
bleaching  powers,  and  are  very  unstable. 

Chlokic  Acid. — This  acid  is  not  of  any  value  in  a  separate 
form,  and  is  obtained  with  difficulty ;  but  it  is  easil  y  enough 
obtained  in  combination.  When  chlorine  gas  is  passed  through 
a  solution  of  caustic  potash,  it  is  rapidly  absorbed.  This,  by 
standing  some  time,  or  by  the  application  of  a  little  heat,  be- 
comes converted  into  a  mixed  salt  of  chloride  of  potassium  and 
chlorate  of  potash.    Thus — 

6C1,  6K0=5C1  K,  CI  Og  K. 

The  chlorate  of  potash  being  less  soluble  than  the  chloride, 
it  is  easily  separated  by  crystallizing.  Chlorate  of  potash  has 
very  strong  detonating  powers,  and  should  be  used  with  great 
care  by  the  student,  especially  when  mixing  it  with  any  other 
substance,  as  these  are  often  explosive.  It  is  extensively  used 
for  lucifer  matches.  We  are  not  aware  that  this  salt  is  used  to 
a  great  extent  as  yet  in  the  dye-house;  but  from  the  property  it 
possesses  of  giving  off  oxygen  easily,  it  may  be  made  very  use- 
ful in  many  operations,  where  oxidation  is  an  object.  It  is  be- 
coming extensively  used  in  calico  print-works. 

Chloric  acid  combines  with  other  bases  besides  potash.  These 
compounds  were  for  a  long  time,  and  are  occasionally  still  termed 
hyper -oxy  muriates. 

Hyperchloric  Acid  is  formed  from  the  chlorate  of  potash. 
It  may  be  obtained  in  combination  with  potash,  by  acting  upon 
the  above  named  salt  with  nitric  acid,  and  putting  the  whole 
afterwards  into  a  small  portion  of  boiling  water;  on  cooling, 
the  hyperchlorate  of  potash  separates  in  crystals.  The  acid 
may  be  separated  from  the  base  by  boiling  it  with  fluosilicic 
acid,  when  the  hyperchloric  acid  remains  in  solution.  This  ,  * 
acid,  or  its  salts,  has  no  bleaching  properties.  It  is  an  interest- 
ing compound  in  its  chemical  relations,  but  not  yet  of  much 
importance  to  the  arts. 

Hydrochloric  Acid. — Chlorine  unites  with  hydrogen,  and 
forms  an  important  compound,  hydrochloric  acid  (muriatic 
acid).  It  is  a  gaseous  substance,  very  soluble  in  water,  in  which 
state  it  is  used,  and  has  been  known  since  a  very  early  period 
in  history  under  the  names  of  marine  acid,  spirit  of  salt,  &c. 
Hydrochloric  acid  is  easily  obtained  by  the  action  of  sulphuric 
acid  on  common  salt.  It  is  prepared  on  the  large  scale,  by 
pouring  vitriol  on  common  salt,  in  a  furnace  prepared  for  the 
purpose;  the  fumes  passing  off  are  absorbed  by  water,  which 
thus  becomes  liquid  hydrochloric  acid,  weak  at  first,  but  it  is 
afterwards  concentrated  by  distillation.  The  reaction  going  on 
during  the  preparation  may  be  thus  represented  : — 

NaCl  S04  H=NaS04,  CI  H. 


HYDROCHLORIC  ACID. 


71 


The  sulphuric  acid  is  generally  used  in  a  diluted  state,  so 
that  there  is  always  a  great  quantity  of  watery  vapor  passing 
off  with  the  gas.  This  acid  combines  with  bases,  and  forms  a 
series  of  important  salts.  That  from  which  it  is  obtained,  viz. 
chloride  of  sodium,  is  a  good  example.  It  is  matter  of  inquiry, 
as  we  have  before  stated,  whether  this  acid  be  capable  of  com- 
bining with  bases,  or  if  it  is  not  decomposed,  and  water  formed 
along  with  the  chloride  of  the  base.  As,  for  instance,  if  hydro- 
chloric acid  be  added  to  nitrate  of  silver,  a  white  precipitate  is 
formed,  which,  if  collected  and  analyzed,  will  be  found  to  be 
composed  of  chlorine  and  silver.  Ag  CI,  not  H  CI  and  Ag  0, 
the  action  having  been — 

Nitrate  of      fN06   Nitric  Acid. 

Silver.        (Ag.  ^^^^ 

Hydrochloric  f  H...  -^><\^^ 

Acid.       1 01...   Chloride  of  silver. 

But  if  we  dissolve  a  piece  of  zinc  in  hydrochloric  acid,  and 
evaporate  to  dryness,  we  get  a  white  powder,  which,  on  analysis, 
will  give  zinc,  chlorine,  and  water,  in  single  equivalents.  The 
question  then  is,  whether  these  elements  do  not  arrange  them- 
selves:— 

Water. 


Chloride  of  Zinc. 
Forming  chloride  of  zinc  with  water. 

H   — Hydrochloric  acid. 

Or  as  <  ><^" 

Zn  — ^  Oxide  of  Zinc. 

Forming  Muriate  of  Zinc. 

We  have,  at  the  risk  of  repetition,  introduced  this  here, 
knowing  that  there  is  confusion  in  these  names  among  practical 
men,  and  have  only  again  to  state  that  all  muriates  should  be 
properly  termed  chlorides.  Some  authors,  to  make  a  distinc- 
tion, call  salts  that  are  in  union  with  water,  such  as  the  zinc 
salt  above,  muriates,  and  only  dry  salts,  as  that  of  silver, 
chlorides.  The  terms,  when  thus  understood,  may  be  used 
synonymously,  so  that  no  confusion  need  occur  on  that  head. 
When  hydrochloric  acid  is  exposed  to  the  air,  it  emits  white 
fumes,  which  is  hydrochloric  acid  gas  with  a  little  watery 
vapor  ;  hence  exposure  weakens  the  acid,  and  should  be  avoided 
as  much  as  possible  in  the  dye-house.    This  gas,  besides,  cor- 


72 


HYDROCHLORIC  ACID. 


rode?  rapidly  any  substance  it  comes  into  contact  with;  and 
destroys  colors.  It  is  a  colorless  acid  when  pure,  but  exposure 
to  the  light  renders  it  of  a  yellow  color;  strong  sunshine  de- 
composes it,  and,  of  course,  should  be  avoided. 

The  common  impurities  in  this  acid  are  iron,  sulphuric  acid, 
and  sulphurous  acid.  The  iron  may  be  detected  by  adding  to 
a  little  of  the  dilute  acid  a  drop  of  gallic  acid.  Sulphuric  acid 
may  be  detected  by  adding  a  solution  of  chloride  of  barium 
to  some  of  the  acid  diluted  with  distilled  water:  which  gives 
a  white  precipitate  with  sulphuric  acid.  If  the  clear  solution 
filtered  from  this  test  be  boiled  with  a  little  nitric  acid,  any 
sulphurous  acid  will  be  converted  into  sulphuric  acid,  which 
will  be  precipitated  by  the  barium,  and  its  presence  detected. 
Different  chloride  salts,  such  as  common  salt,  are  sometimes 
added  to  hydrochloric  acid,  to  give  it  weight  and  specific 
gravity.  This  admixture  may  be  detected  by  evaporating  a 
little  of  the  acid  in  a  small  porcelain  saucer,  or  on  a  piece  of 
glass,  and  seeing  if  any  residue  be  left.  Pure  acid  should  leave 
nothing;  if  the  residue  is  of  a  brown  color,  it  indicates  iron. 
If  the  acid  is  found  by  these  tests  to  be  pure,  then  the  specific 
gravity  may  be  taken  to  ascertain  its  strength.  The  following 
table  will  serve  as  a  guide : — 

Acid  of  Spec.  Grav. 


1.20  in  100  parts.  Specific  Gravity.  Muriatic  Acid, 

100    1.2000    40.777 

99    1.1982    40.369 

98  ....    .  1.1964    39.961 

97    1.1946    39.554 

96    1.1928    39.146 

95    1.1910    38.738 

94    1.1893    38.330 

93    1.1875    37.923 

92    1.1857    37.516 

91    1.1846    37.108 

90    1.1822    36.700 

89    1.1802    36.292 

88    1.1782    35.884 

87    1.1762  .....  35.476 

86    1.1741    35.068 

85    1.1721    34.660 

84  ....    .  1.1701    34.252 

83    1.1681    33.845 

82    1.1661  .....  33.487 

81    1.1641    33.029 

80    1.1620    32.621 

79    1.1599    32.213 


HYDROCHLORIC  ACID. 


Acid  of  Spec.  Grav. 


1.20  in  100  parta.  Specific  Gravity.  Muriatic  Acid. 

78    1.1578    31.805 

97    1.1557  .....  31.398 

76    1.1536    30.990 

75    1.1515    30.582 

74   1.1494    30.174 

73    1.1473    29.767 

72    1.1452    29.359 

71    1.1431    28.951 

70    1.1410    28.544 

69    1.1389    28.136 

'    68    1.1369    27.728 

67    1.1349    27.321 

66    1.1328    26.913 

65    1.1308    26.505 

64    1.1287    26.098 

63    1.1267    25.690 

62    1.1247    25.282 

61    1.1226    24.874 

60    1.1206    24.466 

59    1.1185    24.058 

58    1.1164    23.650 

57    1.1143    23.242 

56    1.1123    22.834 

55    1.1102    22.426 

54    1.1082    22.019 

53    1.1061    21.611 

52    1.1041    21.203 

51    1.1020    20.796 

50    1.1000    20.388 

49    1.0980    19.980 

48    1.0960    19.572 

47    1.0939    19.165 

46    1.0919    18.757 

45    1.0899    18.349 

44    1.0879    17.941 

43    1.0859    17.534 

42    1.0838    17.126 

41  ....   .  1.0818   16.718 

40    1.0798    16.310 

39    1.0778    15.902 

38    1.0758    15.494 

37    1.0738  .....  15.087 

36    1.0718    14.679 

35    1.0697    14.271 


74 


CHLORIDE  OF  NITROGEN". 


Acid  of  Spec.  Grav. 

1.20  in  100  parts.  Specific  Gravity.  Muriatic  Acid. 

34    1.0677    13.-62 

33    1.0657  .....  13.456 

32    1.0636    13.049 

31    1.0617    12.641 

30    1.0597    12.233 

29    1.0577    11.825 

28    1.0557    11.418 

27    1.0537    11.010 

26    1.0517    10.602 

25    1.0497    10.194 

24    1.0477    9.786 

23    1.0457    9.379 

22    1.0437    8.971 

21    1.0417    8.563 

20    1.0397    8.155 

19    1.0377    7.747 

18    1.0357    7.340 

17    1.0337    6.932 

16  .....    .  1.0318    6.524 

15    1.0298    6.116 

14    1.0279  .....  5.709 

13    1.0259    5.301 

12    1.0239    4.893 

11    1.0220    4.486 

10    1.0200    4.078 

9    1.0180    3.670 

8    1.0160    3.262 

7    1.0140    2.854 

6    1.0120    2.447 

5    1.0100    2.039 

4    1.0080    1.931 

3    1.0060    1.224 

2    1.0040    0.816 

1    1.0020    0.408 


Chloride  of  Nitrogen. — Chlorine  combines  with  nitrogen 
to  form  NC13,  which  is  one  of  the  most  explosive  compounds 
known.  It  is  a  heavy  liquid  substance,  and,  from  its  dangerous 
properties,  cannot  be  of  any  use  to  the  dyer. 

Chlorine  also  combines  with  some  of  the  other  non-metallic 
elements,  such  as  phospborus,  sulphur,  carbon,  &c,  and  forms 
compounds,  some  of  which  are  interesting  in  a  chemical  point 
of  view,  but  not  in  respect  to  their  practical  use  in  the  dye- 
house.   The  chlorides  of  the  metals,  however,  are  some  of  them 


BLEACHING. 


75 


important,  and  will  be  described  as  they  occur,  under  the 
metals. 

The  great  use  of  chlorine  in  the  dye-house  is  as  a  bleaching 
agent — into  the  consideration  of  which  we  will  now  enter  a 
little  more  in  detail. 

While  treating  of  light  (p.  25),  we  had  occasion  to  notice 
the  necessity  of  goods  being  a  pure  white  previous  to  being 
dyed  any  light  fancy*  shade ;  otherwise,  the  natural  yellow  color 
of  the  goods,  whether  cotton,  silk,  or  woollen,  would  interfere 
with  the  particular  shade  wanted.  If,  for  example,  the  shade 
required  be  a  light  pink  upon  cotton,  and  a  little  safflower,  the 
stuff  used  for  dyeing  pink,  be  put  upon  it,  unbleached,  the 
resulting  color  would  not  be  a  pink,  but  a  shade  intermediate 
between  a  salmon  and  a  brick  color,  from  the  yellow  ray  re- 
flected from  the  cotton  mixing  with  the  red  reflected  from  the 
dye.  We  must,  therefore,  before  dyeing  a  light  pink,  get  rid  of 
these  yellow  rays,  and  this  is  effected  by  the  process  of  bleach- 
ing.   Hence,  the  dyer  must,  of  necessity,  be  also  a  bleacher. 

Where  and  when  the  practice  of  bleaching  cloth  first  began, 
we  have  no  account ;  but  we  may  reasonably  suppose  that,  as 
soon  as  man  became  so  far  civilized  as  to  manufacture  clothing, 
the  constant  exposure  of  that  clothing  to  the  atmosphere,  and 
occasional  washing,  would  naturally  suggest  the  idea  of  bleaching. 
However,  we  know  that  bleaching  is  of  very  ancient  origin, 
mention  being  made  of  it  in  the  oldest  books  extant.  What 
was  the  nature  of  the  process  practised  in  those  early  times  is 
not  clear ;  but  from  the  earliest  description  to  the  close  of  last 
century,  no  other  process  was  known  but  alternate  boiling,  and 
exposure  to  the  atmosphere,  a  process  which  required  a  num- 
ber of  months  to  complete ;  but,  since  the  application  of  chlo- 
rine to  this  purpose,  an  application  which,  as  Professor  Graham 
observes,  "is  one  of  the  most  valuable  which  chemistry  has 
presented  to  the  arts,"  the  process  is  completed  in  a  few  days ; 
nay,  for  the  most  of  dyeing  operations,  in  a  few  minutes. 

As  many  are  now  unacquainted  with  the  routine  of  the  pro- 
cess of  bleaching  previous  to  the  introduction  of  chlorine,  it 
may  be  worth  while  to  give  a  short  description  of  it,  to  illus- 
trate the  advantages  obtained  from  the  application  of  science 
to  the  arts.  The  first  operation  was  that  of  steeping,  which 
was  merely  immersing  the  yarn  in  hot  water  or  cold  alkaline 
lyes.  When  water  was  used,  the  steeping  lasted  for  three  or 
four  days,  but  with  alkaline  lyes  forty-eight  hours  were  suffi- 
cient ;  the  goods  were  then  washed,  and  boiled  in  an  alkaline 

*  This  is  a  technical  term  for  fugitive  colors,  or  colors  not  fast. 


76 


BLEACHING. 


lye  for  four  or  five  hours  ;  washed  and  exposed  on  the  grass  for 
two  or  three  weeks ;  again  boiled  or  bucked,  which  is  a  techni- 
cal term  for  boiling;  washed  and  crofted,  a  technical  term  for 
exposing  on  the  grass,  as  before.  These  alternate  operations  of 
bucking,  washing,  and  crofting,  were  generally  repeated  four  or 
five  times,  each  time  reducing  the  strength  of  the  alkaline  lyes 
in  which  the  bucking  was  performed. 

The  next  process  was  that  of  souring,  which  till  nearly  the 
middle  of  the  last  century,  consisted  in  steeping  the  goods  for 
several  weeks  in  soured  butter-milk.  This  process  was  much 
shortened  by  Dr.  Home,  who  suggested  the  use  of  sulphuric 
acid  (vitriol)  instead  of  milk ;  and  twelve  hours,  with  a  sour 
of  this  acid,  were  sufficient.*  After  the  first  souring,  the  opera- 
tions of  boiling,  washing,  souring,  and  crofting  were  repeated  in 
regular  rotation,  until  the  yarn  came  to  a  good  color,  and  was 
considered  perfectly  clear.  A  quantity  of  soap  was  generally 
used  in  the  last  operations  of  boiling.  The  number  of  times 
these  operations  were  repeated  varied  according  to  the  quality 
of  the  goods;  linen  was  seldom  finished  in  less  than  six  months, 
and  cotton  goods  varied  from  six  weeks  to  three  months. 

Various  opinions  were  advanced  to  explain  the  nature  of  the 
chemical  changes  induced  during  these  operations;  but  such 
opinions  could  be  only  hypothetical  so  long  as  the  composition 
of  the  atmosphere  and  of  water  were  not  known,  two  substances 
which  acted  a  very  prominent  part  in  these  operations,  and  also 
while  we  were  ignorant  of  the  nature  of  the  coloring  matter 
upon  the  goods,  and  its  composition.  We  have  already  given 
the  composition  of  water  and  air,  but  the  composition  of  the 
coloring  matter  upon  cotton,  &c,  has  not  as  yet  been  very  accu- 
rately ascertained.  Its  properties  are  neutral,  and  of  a  resinous 
nature,  from  which,  as  a  general  principle,  we  may  safely  say, 
that  the  neutral  is  composed  of  hydrogen  and  carbon  with 
oxygen;  and,  from  the  composition  of  resinous  matters  in 
general,  it  will  be  composed  of  hydrogen  and  carbon,  and  soluble 
in  alkalies  and  water,  and  therefore  mostly  all  taken  out  by 
steeping  and  boiling.  These  resinous  and  coloring  matters  do 
not  form  a  part  of  the  cotton  but  mechanically  adhere  to  it,  so 
that  substances  may  act  upon  and  decompose  them  without  in 
the  least  destroying  the  cotton  ;  indeed,  from  a  number  of  expe- 
riments, cotton  is  found  as  strong  when  deprived  of  these  sub- 
stances as  before. 

In  boiling  cotton  yarn  in  water  alone,  it  loses  considerably 
in  weight ;  different  qualities  of  cotton  varying  in  this  respect ; 
fine  qualities  lose  least.    From  a  number  of  experiments,  made 


*  Home  on  Bleaching. 


BLEACHING. 


77 


expressly  to  ascertain  this  point,  and  with  various  qualities  of 
cotton,  the  average  of  loss  may  be  taken  at  5  per  cent,  of  the 
weight  of  the  cotton. 

In  order  to  ascertain  the  chemical  changes  which  take  place 
when  goods  are  bleached  in  the  air,  M.  Berthollet,  finding  that 
those  seasons  when  most  dew  was  deposited,  were  the  most 
effective  upon  the  color,  examined  the  dew  which  falls  from  the 
atmosphere,  and  also  that  which  transpires  from  the  grass,  and 
found  both  to  contain  a  sufficient  quantity  of  oxygen  to  destroy 
the  color  of  turnsole  or  litmus  paper.*  What  errors  led  to  these 
results  we  do  not  know,  for  although  dew  did  contain  oxygen, 
it  would  not  give  it  acid  properties  to  redden  turnsole  paper. 
Or  whether  M.  Berthollet  considered  the  bleaching  property  of 
dew  owing  to  its  having  free  oxygen,  or  to  this  acid  property, 
we  do  not  know,  not  having  seen  the  original  details.  Gould 
we  suppose  the  formation  of  peroxide  of  hydrogen  (page  58), 
the  effects  would  be  easily  explained.f  The  theory  of  croft 
bleaching  has  been  explained  variously  as  follows: — 

1.  The  oxygen  of  the  atmosphere  combines  with  the  color- 
ing matter  of  the  cotton,  forming  a  new  substance  capable  of 
solution  in  water  or  alkalies,  and  comes  off  by  washing  or 
boiling;  or  it  combines  with  some  of  the  elements  of  the  color- 
ing matter,  such  as  the  carbon,  forming  carbonic  acid  gas,  which 
escapes  into  the  air,  or  with  the  hydrogen,  and  forms  water; 
those  elements  which  are  left,  form  either  colorless  substances, 
or  substances  soluble  in  the  next  operation. 

2.  The  oxygen  combines  directly  with  the  coloring  matter, 
forming  a  permanent  and  colorless  oxide. 

3.  The  water  acts  otherwise  than  being  merely  a  solvent; 
that  it,  or  one  of  its  elements,  combines  with  the  coloring  sub- 
stance producing  the  effects  noticed  in  the  first  proposition. 
Hence  dew  being  pure  and  free  from  any  admixture  which 
might  retard  this  union,  is  better  fitted  for  bleaching;  conse- 
quently, in  seasons  when  most  dew  is  deposited,  the  bleaching 
process  will  be  accelerated.  Which  of  these  theories  is  the  true 
one,  we  cannot  say ;  but  we  know  that  light  facilitates  the  process 
of  bleaching,  and  this  circumstance,  we  think,  favors  the  sup- 
position of  the  coloring  matter  being  decomposed.  Other  in- 
teresting theories  might  be  advanced  from  phenomena  observed 
during  the  process  of  croft  bleaching ;  and  also  the  part  that 
boiling  in  alkali  and  the  sours  take  in  the  operation. 

The  modern  process  of  bleaching,  and  that  which  is  now 
almost  universally  practised,  is  by  means  of  chlorine.  This 
substance,  as  has  been  mentioned  (page  68),  was  discovered  by 


*  Parke's  Chemical  Essays. 


f  See  Ozone. 


78 


BLEACHING. 


Scheele,  who  also  described  its  peculiar  property  of  destroying 
vegetable  coloring  matters ;  but  M.  Berthollet  was  the  first  who 
called  the  attention  of  the  public  to  its  value  as  a  bleaching 
agent,  in  1785.  About  the  time  this  chemist  was  prosecuting 
his  inquiries  into  the  nature  of  this  substance,  he  was  visited 
by  the  celebrated  James  Watt,  to  whom  Berthollet  related  the 
results  of  his  experiments  upon  bleaching,  and  from  this  cir- 
cumstance the  inventor  of  the  modern  steam-engine  became 
also  the  introducer  of  the  new  process  of  bleaching  into  this 
country.* 

The  introduction  of  chlorine,  as  a  bleaching  agent,  like  all 
other  discoveries  which  tend  to  overturn  old  practices,  met 
with  a  host  of  opposition.  The  most  prominent  objections 
offered  were,  that  it  destroyed  the  cloth,  did  not  give  a  perma- 
nent white,  and  that  it  killed  the  men  who  wrought  with  it. 
These  statements  were  not  altogether  groundless,  but  the  force 
with  which  they  were  urged  hastened  improvements,  and 
effected  remedies.  The  first  method  of  using  chlorine  was  by 
saturating  cold  water  with  the  gas,  the  water  taking  up  about 
twice  its  volume  of  it.  The  goods  were  put  into  this  water, 
after  which  it  was  heated  to  drive  off  the  chlorine,  or  set  it  free 
that  it  might  act  upon  the  coloring  matter  ;  but,  the  goods  being 
impaired  by  this  process,  even  when  the  greatest  care  was  taken, 
suggested  the  diluting  of  the  chlorine  water;  which  diluted 
liquor  was  found  to  bleach  equally  well,  and  the  goods  were 
preserved.  The  defect  of  the  goods  becoming  yellow  after  a 
few  days,  suggested  alternate  boiling  with  alkaline  lyes ;  and 
the  difficulty  arising  from  the  workmen  being  unable  to  endure 
the  effects  of  the  escaping  gas,  led  to  the  discovery  that  alkalies 
not  only  absorb  a  greater  quantity  of  chlorine  than  water,  but 
that  they  hold  it  with  greater  affinity,  not  allowing  the  gas  to 
escape  and  affect  the  atmosphere,  at  the  same  time  parting 
with  it  more  regularly  and  effectively  to  the  goods.  The  alka- 
lies used  were  soda  and  potash,  and  each  bleaching- work  had 
its  regular  apparatus  of  retorts  and  carboys,  or  wooden  chests, 
for  the  purpose  of  making  their  own  chloride  of  potash  or 
soda.  This  practice  is  still  continued  in  many  print-works, 
both  in  Scotland  and  England,  for  particular  fabrics  or  delicate 
operations,  as  it  is  considered  much  safer  and  better  adapted 
for  certain  purposes  than  the  common  bleaching  powder.  In 
the  year  1798,  Mr.  Tennant,  of  Glasgow,  patented  a  process  for 
using  a  solution  of  lime  for  absorbing  the  chlorine  instead  of 
potash  and  soda;  shortly  after,  the  hydrate  of  lime  (slaked 

*  Some  give  this  honor  to  Professor  Copland,  of  Aberdeen  ;  but,  from  the 
evidence  we  have  seen,  it  belongs  to  Watt,  although  the  difference  of  time 
was  but  little. 


BLEACHING. 


79 


lime)  was  substituted  for  lime-water,  and  this  is  the  preparation 
now  used  for  bleaching,  under  the  names  of  bleaching  powder 
and  chloride  of  lime.  Other  minor  improvements  have  been 
made  regarding  the  quantity  of  chlorine  absorbed  by  the  lime 
under  certain  conditions,  which  will  be  noticed  afterwards. 

Notwithstanding  all  these  discoveries  and  applications,  the 
real  nature  of  the  decoloring  agent  was  still  unknown ;  it  was 
prepared  by  digesting  together  a  mixture  of  common  salt,  per- 
oxide of  manganese,  and  sulphuric  acid.  A  decomposition  took 
place,  which  was  explained  as  follows :  The  sulphuric  acid  com- 
bined with  the  soda  of  the  salt  and  set  the  muriatic  acid,  which 
was  in  union  with  the  soda,  at  liberty.  The  oxide  of  manga- 
nese gave  off  a  part  of  its  oxygen,  which  combined  with  the 
free  muriatic  acid  and  formed  oxygenated  muriatic  acid,  a  name 
which  was  first  applied  to  this  new  substance ;  but  after  being 
introduced  into  the  arts,  this  name  was  considered  too  unwieldy 
for  common  use,  and  was  therefore  contracted  into  oxy -muriatic 
acid.  It  was  ultimately  contracted,  by  the  workmen  into  oxygen, 
and  notwithstanding  the  discovery  of  Sir  H.  Davy,  in  1811, 
that  oxy-muriatic  acid  was  not  common  muriatic  acid  with 
more  oxygen,  but  a  simple  body  which  he  called  chlorine,  the 
name  oxygen  is  still  given  to  bleaching  powder  and  all  its 
preparations.  This  is  a  serious  evil  to  the  workmen }  not 
practically,  but  for  their  own  understanding ;  as  it  identifies 
chlorine  with  oxygen,  a  substance  which  effects  reactions  in  the 
operation  of  dyeing,  quite  distinct  from  that  with  which  it  is 
identified.  We  still  remember  the  difficulty  we  were  in,  when 
hearing  that  it  was  the  oxygen  of  the  air  that  supported  life, 
and  that  it  was  the  same  oxygen  which  turned  the  green  color 
of  the  goods  while  in  the  vat  to  blue  when  exposed  to  the 
atmosphere,  and  at  the  same  time,  seeing  bleaching  liquor, 
which  was  also  termed  oxygen,  destroying  blues,  and  felt  that 
we  could  not  breathe  its  gas  but  with  the  greatest  difficulty. 
To  solve  this  puzzle,  every  chemical  book  we  could  find  was 
examined  for  remarks  on  oxygen  ;  but,  to  our  mortification, 
not  one  of  these  works  alluded  to  its  bleaching  properties.  We 
doubt  not  but  many  others  have  been  in  the  same  dilemma. 
The  following  order  will  show  our  chemical  friends  the  ridicu- 
lous position  in  which  dyers  and  bleachers  place  themselves  by 
retaining  such  names: — 

"Glasgow,  . 

"Messrs.  *  *  Will  please  send,  at  their  earliest  conve- 
nience, a  cask  of  their  strongest  oxygen,  containing  as  near 
as  possible  2  cwt. ;  let  it  be  newly  made  and  dry ;  the  last  was 
damp,  so  that  in  a  few  days  it  became  like  as  much  clay,  and 


80 


BLEACHING  POWDER. 


lost  the  most  of  its  strength.  Your  attention  will  oblige  yours," 
&c.  &c. 

The  dyer  will  do  well  to  turn  to  the  article  oxygen,  and 
peruse  it,  and  then  the  absurdity  of  the  above  order  will  be 
observed. 

We  are  informed  that  chemic  is  a  common  name  for  bleach- 
ing liquor  in  many  print-works ;  and  there  are  many  names 
for  other  substances  equally  unsuitable.  We  will  give  a  table 
of  these  technical  terms  with  their  proper  designations  in 
another  part  of  the  volume.  In  the  mean  time,  we  state  that 
there  is  no  better  name  for  the  substance  we  have  been  de- 
scribing than  bleaching  powder,  or,  if  in  solution,  bleaching 
liquor. 

Bleaching  powder  is  prepared  by  exposing  the  hydrate  of 
lime  (slaked  lime)  tp  an  atmosphere  of  chlorine  gas  till  the  lime 
ceases  to  absorb  the  gas.  In  practice,  it  is  found  that  when  the 
lime  is  in  combination  with  an  extra  equivalent  of  water,  it  will 
absorb  much  more  chlorine  than  when  it  has  just  as  much 
water  as  slakes  it.  The  chlorine  is  passed  into  large  vessels  or 
chambers  furnished  with  shelves,  upon  which  the  lime  is  placed. 
Bleaching  powder  is  white  and  pulverulent ;  it  has  a  hot,  bitter, 
and  astringent  taste,  and  a  peculiar  smell.  When  digested  in 
water,  carbonate  of  lime  and  some  other  impurities  remain. 

Some  of  the  continental  chemists  first  suggested  that  the 
chlorine  was  not  merely  absorbed  and  retained  by  the  lime,  but 
that  it  combined  with  it,  and  formed  one'or  more  definite  com- 
pounds. This  has  led  to  a  great  deal  of  research,  but  scarcely 
to  any  definite  conclusions,  as  there  are  various  compounds  of 
chlorine  with  oxygen,  which  may  be  formed  during  the  pre- 
paration of  bleaching  powder,  and  which  possess  bleaching 
properties  as  well  as  the  chlorine  alone.  The  most  general  sup- 
position is,  that  hypochlorite  of  lime  is  formed,  and  that  on  this 
salt,  and  its  decomposition,  depend  the  operations  of  bleaching. 
This  opinion  is  well  founded,  and  may  be  taken  as  expressing 
the  true  composition  of  bleaching  powder,  which  is  therefore  to 
be  regarded  as  a  definite  salt  of  lime  and  hypochlorous  acid, 
with  chloride  of  calcium  and  hydrate  of  lime;*  thus,  CaOOlO-f 
CaCl  +  CaOHO. 

The  best  bleaching  powder  of  commerce  seldom  contains 
above  thirty  per  cent,  of  chlorine  available  in  bleaching ;  but 
there  are  few  of  the  substances  employed  by  the  dyer  or 
bleacher  more  liable  to  change ;  indeed,  from  its  first  formation, 

*  Whoever  is  desirous  of  entering  into  the  merits  of  the  researches  made 
upon  the  chemical  character  of  bleaching  powder,  will  find  a  series  of  valua- 
ble papers  upon  the  subject,  by  Balard,  in  the  second  volume  of  the  General 
Records  of  Science.  * 


BLEACHING  POWDER. 


81 


there  seems  to  be  a  constant  chemical  action  going  on  between 
the  chlorine  and  the  lime  ;  oxygen  is  disengaged,  and  chloride 
of  calcium  formed,  a  substance  which  possesses  no  bleaching 
properties.  These  changes  may  be  much  retarded  by  keeping 
the  powder  perfectly  dry,  or  by  dissolving  it  in  cold  water,  and 
keeping  the  solution  excluded  from  the  air.  Chloride  of  lime 
(bleaching  powder)  does  not  attract  moisture  from  the  atmos- 
phere, as  is  supposed  by  dyers ;  but,  when  exposed,  it  is  rapidly 
changed  into  chloride  of  calcium,  a  substance  that  is  very  deli- 
quescent, and  allowing  that  the  lime  previously  contained  two 
atoms  of  water,  these  combine  with  the  chloride  of  calcium, 
when  formed,  and  place  this  salt  in  the  best  circumstances  for 
attracting  more  water  from  the  air,  thus  hastening  the  destruc- 
tion of  the  remaining  chloride  of  lime.  We  have  seen  good 
bleaching  powder  by  a  little  inattention  reduced  to  this  state 
in  a  few  weeks,  and  its  bleaching  properties  almost  totally 
destroyed. 

As  chloride  of  lime  loses  its  bleaching  properties  by  standing 
and  several  other  circumstances,  it  is  of  the  utmost  consequence 
to  the  consumer  that  he  should  have  some  means  of  determining 
its  real  value,  both  for  the  sake  of  safety  and  accuracy  in  his 
processes,  and  its  commercial  worth.  We  have  seen  bleaching 
powder,  which  did  not  contain  above  ten  per  cent,  of  chlorine, 
charged  and  paid  for  at  the  same  rate  as  that  which  contained 
thirty  per  cent.;  but  not  having  the  means  of  testing  it  pre- 
viously, the  quality  was  not  discovered  till  the  salt  was  in  solu- 
tion ;  indeed,  we  are  not  aware  of  any  relative  prices  according 
to  the  quality  of  this  article,  although  with  a  very  little  care 
and  trifling  expense  the  dyer  may  know  the  value  of  the  article 
he  is  about  to  purchase,  and  of  course  only  pay  accordingly. 
The  first  method  of  determining  the  value  of  bleaching  powder 
was  by  sulphate  of  indigo,  but  the  indigo  solution  alters  by 
keeping,  and  is  therefore  objectionable.  u Several  exact 
methods,"  says  Graham,  in  his  Elements  of  Chemistry,  "of  which 
that  in  which  sulphate  of  iron  is  used  appears  to  be  entitled  to 
preference.  This  method  is  based  upon  the  circumstance  that 
the  chlorine  of  chloride  of  lime  converts  a  salt  of  the  protoxide 
into  a  salt  of  the  peroxide  of  iron.  It  is  found  by  experience 
that  ten  grains  of  chlorine  are  capable  of  peroxidizing  78  grains 
of  crystallized  sulphate  of  iron.  In  an  experiment  to  determine 
the  percentage  of  chlorine  in  a  sample  of  bleaching  powder, 
some  good  crystals  of  protosulphate  of  iron  (copperas)  are  to  be 
pounded  and  dried  by  pressing  between  folds  of  cloth ;  78 
grains  are  dissolved  in  about  two  ounces  of  water,  acidulated 
by  a  few  drops  either  of  sulphuric  or  muriatic  acid  ;  then  50 
•grains  of  the  chloride  of  lime  to  be  examined,  are  dissolved  in 
t5 


82 


BLEACHING  POWDEK. 


about  two  ounces  of  water,  by  rubbing  them  together  in  a 
mortar,  and  the  whole  poured  into  a  vessel  graduated  into  a 
hundred  parts.  The  common  alkalimeter  will  do.  This  is  a 
straight  glass  tube,  or  generally  a  very  narrow  jar  about  five- 
eighths  of  an  inch  in  width,  and  14  inches  high,  mounted  upon 
a  foot,  as  shown  in  the  accompanying  figure,  capable  at  least 
of  containing  a  thousand  grains  of  water,  and  graduated  into  a 
hundred  parts.  The  jar  containing  the  50 
Fig.  6,  grains  of  chloride  of  lime  is  filled  up  to  the 

highest  graduation  by  the  addition  of  water, 
and  the  whole  is  well  mixed.  The  clear  part 
of  this  solution  is  gradually  poured  into  the 
solution  of  sulphate  of  iron,  till  the  latter  is 
completely  peroxidized.  This  is  known  by 
means  of  red  prussiate  of  potash,  which  gives 
a  blue  precipitate  with  the  protoxide,  but  not 
with  the  peroxide  of  iron.  A  white  plate  of 
porcelain  or  glass  is  spotted  over  with  small 
drops  of  the  prussiate;  a  drop  of  iron  solu- 
tion is  mixed  with  one  of  these  after  every 
addition  of  chloride  of  lime ;  and  the  additions 
continued  so  long  as  the  prussiate  drops  are 
colored  blue.  They  may  be  colored  green,  but 
that  is  of  no  moment.  When  the  iron  is  per- 
oxidized, the  number  of  graduations  or  measures  of  chloride  of 
lime  required  to  produce  that  effect  is  noted  ;  the  quantity  of 
chlorine  in  the  50  grains  of  bleaching  powder  is  now  known, 
being  ascertained  by  proportion.  Thus,  if  it  requires  68  mea- 
sures of  the  bleaching  solution,  then,  as  68  is  to  10,  so  100  is  to 
14,7,  the  chlorine  in  the  fifty  grains  of  powder;  this  being 
multiplied  by  two  gives  the  percentage  of  chlorine  in  the  sam- 
ple, which  is  29.4."  We  have  found  in  operating  in  this  way, 
a  liability  to  lose  a  little  chlorine  as  gas.  This  is  obviated  by 
having  the  iron  solution  in  a  stoppered  bottle,  and  upon  every 
addition  of  bleaching  liquor  to  put  in  the  stopper  and  shake  the 
bottle. 

Another  process  has  been  recommended  by  Gay-Lussac, 
which  combines  simplicity  with  accuracy,  and  is  coming  into 
general  use  with  the  manufacturers  of  bleaching  powder.  A 
solution  of  arsenious  acid  is  made  in  muriatic  acid,  and  diluted 
with  water.  On  adding  a  solution  of  chloride  of  lime,  the 
muriatic  acid  takes  the  lime  ;  the  chlorine  decomposes  the 
water,  combining  with  its  hydrogen,  while  the  oxygen  unites 
with  the  arsenious  acid,  and  converts  it  into  arsenic  acid. 
When  the  arsenious  solution  is  tinged  with  sulphate  of  indigo, 
and  bleaching  liquor  added,  there  is  no  change  taking  place  on 


BLEACHING  POWDER. 


83 


the  indigo  until  the  whole  arsenious  acid  is  transformed  into 
arsenic  acid  ;  but  the  first  drop  after  this  discolors  the  indigo. 
The  correctness  of  this  test  is  founded  upon  the  knowledge  of 
what  proportion  of  chlorine  is  necessary  to  oxidize  the  arsenious 
acid  in  the  test  solution.  Various  proportions  have  been  pro- 
posed as  the  standard  strength  of  the  solution,  but  it  does  not 
matter  much  what  proportions  are  used,  provided  the  operator 
knows  what  proportion  of  chlorine  is  necessary  to  transform  it, 
and  being  careful  always  to  have  it  the  same.  The  best  pro- 
portions for  general  use  are  those  that  require  the  least  calcu- 
lation. The  following  proportions  we  have  found  to  do  very 
well/and  to  be  easily  counted:  Take  one  ounce  of  arsenious 
acid  (common  arsenic  of  the  shops),  and  dissolve  it  by  diges- 
tion for  a  few  minutes  at  a  boiling  heat,  in  24  ounces  by  mea- 
sure of  pure  muriatic  acid,  then  add  46  ounces  by  measure  of 
distilled  water;  bat  in  case  of  any  loss  by  evaporation  during 
digestion,  it  is  better  to  have  a  vessel  which  contains  up  to  a 
certain  mark  70  ounces,  and  when  the  acid  solution  is  put  into 
it,  to  fill  up  to  the  mark  with  water.  This  may  be  bottled  and 
put  past  as  the  standard  test  liquor.  Every  three  ounces  by 
measure  of  it  are  equivalent  to  twenty-five  grains  of  chlorine. 
When  a  sample  of  bleaching  powder  is  to  be  tried,  two  hun- 
dred grains  are  carefully  weighed  and  dissolved  in  the  manner 
already  described,  in  twice  as  much  water  as  will  fill  the  alkali- 
meter,  or  any  other  vessel  graduated  into  a  hundred  parts. 
Three  ounces  of  the  arsenious  solution  are  measured  out  and 
put  into  a  glass  jar  or  tumbler,  and  tinged  with  sulphate  of 
indigo.  The  alkalimeter  is  now  filled  with  the  bleaching  liquor, 
which  is  added  slowly  to  the  arsenious  solution,  stirring  con- 
stantly, and  watching  every  drop  that  is  added  for  the  decolor- 
ing of  the  indigo.  If  the  sample  be  so  poor  in  chlorine  that 
one  measure  of  the  alkalimeter  will  not  change  the  color  of 
the  indigo,  it  may  be  filled  again,  and  the  process  continued 
till  the  indigo  is  decolored,  and  the  whole  number  of  gradua- 
tions taken  to  effect  this  carefully  noted;  the  fewer  the  num- 
ber of  graduations  required,  the  richer  the  sample  is  in  chlorine. 
Now,  as  every  three  ounces  of  the  test  liquor  contain  arsenious 
acid  equivalent  to  25  grains  of  chlorine,  if  the  hundred  mea- 
sures effect  the  change  of  the  arsenious  into  the  arsenic  acid, 
the  value  of  the  sample  is  exactly  25  per  cent. ;  in  other  words, 
every  four  graduations  taken  to  effect  this  change  indicate  one 
per  cent,  of  chlorine.  These  equivalents  were  practically  de- 
termined, and  may  differ  a  little  from  the  theoretical  calculation 
by  atomic  numbers,  but  the  difference  does  not  vary  above 
half  a  per  cent.,  and  is  not  of  much  consequence  in  practice. 


84 


BLEACHING  POWDER. 


The  following  table  will  serve  as  a  'guide  to  those  who  may 
adopt  oar  proportions  : — 


Mea- 

Per cent. 

Mea- 

Per cent. 

Mea- 

Per cent. 

Mea- 

Per cent. 

sures. 

sures. 

sures. 

sures. 

150 

16.66 

•  127 

19.68 

104 

24.03 

81 

30.86 

149 

16.77 

126 

19.84 

103 

24.27 

80 

31.24 

148 

16.89 

125 

20.00 

102 

24.51 

79 

31.64 

147 

17.00 

124 

20.16 

101 

24.75 

78 

32.05 

146 

17.12 

123 

20.32 

100 

25.00 

77 

32.46 

145 

17.24 

122 

20.49 

99 

25.25 

76 

32.89 

144 

17.36 

121 

20.66 

98 

25.40 

75 

33.33 

143 

17.48 

120 

20.83 

97 

25.77 

74 

33.78 

142 

17.60 

119 

21.00 

96 

26.04 

73 

34.24 

141 

17.73 

118 

21.18 

95 

26.31 

72 

34.72 

140 

17.85 

117 

21.36 

94 

26.58 

71 

35.21 

139 

17.98 

116 

21.55 

93 

26.87 

70 

35.71 

138 

18.11 

115 

21.73 

92 

27.17 

69 

36.23 

137 

18.25 

114 

21.93 

91 

27.48 

68 

36.75 

136 

18.38 

113 

22.12 

90 

27.77 

67 

37.31 

135 

18.51 

112 

22.32 

89 

28.08 

66 

37.87 

134 

18.65 

111 

22.52 

88 

28.40 

65 

38.46 

133 

18.79 

110 

22.72 

87 

28.73 

64 

39.09 

132 

18.94 

109 

22.93 

86 

29.06 

63 

39.68 

131 

19.08 

108 

23.14 

85 

29.41 

62 

40.32 

130 

19.23 

107 

23.36 

84 

29.76 

61 

40.98 

129 

19.38 

106 

23.58 

83 

30.12 

60 

41.26 

128 

19.53 

105 

23.81 

82 

30.48 

The  above  table  includes  almost  the  whole  range  of  per- 
centage of  the  bleaching  powder  of  commerce  ;  but  should  the 
dyer  meet  with  any  not  included  in  the  table,  the  percentage 
may  be  calculated  as  follows.  As  the  number  of  measures  is 
to  100,  so  is  25  to  the  answer  required.  Say,  for  example,  the 
measure  is  160— then  160  :  100:  :  25  :  15.62. 

Any  of  the  two  methods  just  described  may  be  performed 
in  a  few  minutes;  and  in  a  substance  that  is  liable  to  such 
deterioration,  it  is  surely  of  importance  that  the  purchaser 
should  have  some  knowledge  of  the  quality  of  the  article  he  is 
purchasing,  and  that  the  workmen  know  something  of  the 
strength  of  the  substance  they  are  working  with.  Might  not 
a  certain  price  be  fixed  for  a  standard  strength  of  bleaching 
powder,  and  to  rise  and  fall  according  to  the  percentage  of 
chlorine  which  it  contains,  in  the  same  manner  as  practised 
with  soda  ash  ?    It  would  at  least  save  much  annoyance,  and 


BLEACHING  POWDER. 


85 


the  common  complaint,  " that  the  last  cask  was  not  so  good 
as  the  former."  The  average  percentage  of  good  bleaching 
powder  varies  from  25  to  30  per  cent.  Were  this  average 
fixed  at  three  pence  per  pound,  which  has  been  the  constant 
price  of  bleaching  powder  these  some  years,  then  that  which 
contains  from  20  to  25  per  cent,  would  be  2Jd.,  and  from  15 
to  20,  2d.  per  pound,  while  above  30  per  cent,  the  valuQ  ought 
of  course  to  rise  in  the  same  ratio.  The  adoption  of  some 
such  plan,  we  are  confident,  would  be  satisfactory  to  all  parties. 

To  prepare  chloride  of  lime  for  bleaching,  an  aqueous  solu- 
tion is  requisite.  For  this  purpose  a  quantity  is  put  into  a 
large* vessel  filled  with  water,  well  stirred,  and  allowed  to  settle; 
this  is  termed  the  stock  liquor.  There  are  no  definite  propor- 
tions for  making  up  this  vat;  every  bleacher  makes  up  his 
stock-vat  to  a  certain  strength  indicated  by  Twaddell's  hydro- 
meter; a  most  fallacious  test,  as  the  chloride  of  calcium,  and 
every  other  matter  which  is  soluble  in  water,  although  it  has 
no  bleaching  properties,  affects  the  hydrometer.  Care  should 
be  taken  that  this  stock- vat  be  protected  from  the  air  as  much 
as  possible,  as  the  lime  absorbs  carbonic  acid,  and  the  chlorine 
being  set  at  liberty,  occasions  considerable  loss.  This  may  be 
illustrated  by  putting  a  little  of  the  solution  upon  a  flat  plate, 
and  allowing  it  to  stand  a  few  days,  when  it  will  be  found  to 
have  lost  its  bleaching  power  altogether. 

The  first  operation  in  bleaching  cloth  is  steeping  it  in  a 
waste  lye,  or  tepid  water,  for  a  number  of  hours,  generally 
over  night:  this  is  termed  the  rot  steep:  its  object  is  to 
loosen  the  paste  and  dirt  that  may  have  adhered  to  the  cloth 
during  its  manufacture.  This  steep  ought  not  to  be  hotter 
than  bloodheat,  otherwise,  if  oil  be  upon  the  cloth,  it  is  not 
saponified,  neither  is  it  so  easily  taken  out  after;  in  all  cases 
when  oil  is  observed,  it  ought  to  be  taken  out  by  rubbing  it 
with  soft  soap  and  cold  water  previous  to  putting  it  into  the 
steep.  The  goods  are  thoroughly  washed  from  this  steep  in 
the  dash-wheel,  but  if  a  wheel  is  not  convenient,  they  are 
tramped  in  water,  and  then  washed  by  rinsing  them  through 
water  with  the  hands;  they  are  then  ready  for  the  boiler. 
The  boiling  lye  is  made  up  by  taking  strong  caustic  lye  (see 
soda  and  potash),  a  quantity  equal  to  about  six  pounds'  weight 
of  alkali  to  one  hundred  pounds'  weight  of  cloth,  having  as 
much  water  in  the  boiler  as  will  allow  the  goods  sufficient  play 
when  boiling;  they  ought  to  boil  for  three  hours.  When 
goods  are  for  light  delicate  colors,  such  as  Prussian  blues,  the 
success  of  a  bleach  for  such  colors  depends  much  upon  a  good 
boil.  The  goods  are  well  washed  from  the  boil,  and  allowed 
to  drain  ;  the  draining  is  facilitated  by  pouring  hot  water 


86  BLEACHING  POWDER. 

upon  them;  they  are  then  hanked  up,  taking  out  all  the 
twists,  and  laid  into  the  bleaching  liquor  as  loose  as  possible. 
The  vessels  which  contain  this  liquor  are  large,  made  either  of 
stone  or  wood,  and  are  termed  bleaching- vats,  or  troughs.  To 
prepare  this  liquor,  these  troughs  are  filled  with  water,  and 
a  quantity  of  the  stock  liquor  added  until  the 
Fig.  7.         required  strength  is  obtained,  which  is  indicated 


by  its  action  upon  the  sulphate  of  indigo,  in 
what  is  termed  the  test-glass,  a  vessel  of  this 
form.  It  is  filled  to  the  mark  a  with  the  sul- 
phate of  indigo;  this  indigo  is  generally  sup- 
plied by  the  manufacturers  of  the  powder  as 
test  blue,  the  liquor  is  added  drop  by  drop 
until  the  color  of  the  indigo  is  destroyed  ;  the 
quantity  taken  to  effect  this  is  denoted  by  the 
graduations  above;  the  weaker  the  liquor,  the 
greater  the  number  of  graduations  required  ; 


each  of  these  graduations  is  termed  its  degree  ; 
two  degrees  are  considered  a  fair  strength  for  light  goods,  but 
for  heavy  fabrics  it  may  be  made  stronger  ;  they  are  allowred 
to  steep  in  this  for  several  hours,  varying  according  to  the 
nature  of  the  goods.  The  objections  we  had  to  the  use  of  sul- 
phate of  indigo  as  a  test  in  the  former  case  are  equally  applica- 
ble here.  We  have  found  this  test  to  be  very  uncertain.  A 
much  better  method  has  been  adopted  by  Mr.  Walter  Crum,  a 
description  of  which  was  read  by  him  to  the  Glasgow  Philo- 
sophical Society,  and  published  in  the  Report  of  that  Society 
for  1841.  We  quote  the  following  important  paragraphs  of 
the  paper  :— 

"  Chlorimetry  requires  to  be  practised  by  the  bleacher  for 
two  purposes — First,  he  has  to  learn  the  commercial  value  of 
the  bleaching  powder  which  he  purchases;  and  with  that  view 
he  can  scarcely  desire  anything  better  than  the  method  either  • 
by  arsenious  acid  or  green  copperas.  But  the  more  important, 
because  the  hourly  testing  of  his  bleaching  liquor,  and  that  on 
which  the  safety  of  his  goods  depends,  is  the  ascertaining  the 
strength  of  the  weak  solutions  in  which  the  goods  have  to  be 
immersed.  If  the  solution  is  too  strong,  the  fabric  is  apt  to  be 
injured.  If  too  weak,  parts  of  the  goods  remain  brown,  and 
the  operation  must  be  repeated.  The  range  within  which 
cotton  is  safe  in  this  process  is  not  very  wide.  A  solution 
standing  1°  on  TwaddelPs  hydrometer  (spec.  grav.  1.005),  is 
not  more  than  safe  for  such  goods,  while  that  of  half  a  degree 
is  scarcely  sufficient  for  the  first  operation  on  stout  cloth,  unless 
it  is  packed  more  loosely  than  usual.  When  the  vessel  is  first 
set  with  fresh  solution  of  bleaching  powder,  there  is  little  diffi- 


BLEACHING  POWDER. 


87 


culty,  if  the  character  of  the  powder  be  known  ;  but  when  the 
goods  are  retired  from  the  steeping  vessels,  they  leave  a  por- 
tion of  bleaching  liquor  behind,  unexhausted,  which  must  be 
taken  into  account  in  restoring  the  liquor  to  the  requisite 
strength  for  the  next  parcel.  The  chlorimeter  must,  therefore, 
be  applied  every  time  that  fresh  goods  are  put  into  the  liquid. 
It  must,  consequently,  be  intrusted  to  persons  who  may  not  be 
expert  either  in  figures  or  in  chemical  manipulation.  Hence 
all  the  processes  I  have  described  are  too  delicate  and  tedious. 

"I  introduced  another  into  our  establishment  some  years  ago, 
which  has  been  in  regular  use  ever  since,  and  by  which  the 
testing  is  performed  in  an  instant.  It  depends  on  the  depth  of 
color  of  the  peracetate  of  iron.  A  solution  is  formed  of  proto- 
chloride  of  iron,  by  dissolving  cast-iron  turnings  in  muriatic 
acid  of  half  the  usual  strength.  To  insure  perfect  saturation, 
a  large  excess  of  iron  is  kept  for  some  time  in  contact  with  the 
solution  at  the  heat  of  boiling  water.  One  measure  of  this 
solution,  at  40°  Twaddell  (spec.  grav.  1.200),  is  mixed  with  one 
of  acetic  acid,  such  as  Turnbull  &  Co.,  of  Glasgow,  sell  at  8s.  a 
gallon.  That  forms  the  proof  solution.  If  mixed  with  six  or 
eight  parts  of  water  it  is  quite  colorless,  but  chloride  of  lime 
occasions  with  it  the  production  of  peracetate  of  iron,  which 
has  a  peculiarly  intense  red  color. 

"A  set  of  phials  is  procured,  12  in  number,  all  of  the  same 
diameter.  A  quantity  of  the  proof  solution,  equal  to  ^th  of 
their  capacity,  is  put  into  each,  and  then  they  are  filled  up 
with  bleaching  liquor  of  various  strengths,  the  first  at  x^th  of 
a  degree  of  Twaddell,  the  second,  T2oths,  the  third,  T32ths,  and 
so  on  up  to  jf  ths,  or  one  degree.^  They  are  then  well  corked 
up,  and  ranged  together,  two  and  two,  in  a  piece  of  wood,  in 
holes  drilled  to  suit  them.  We  have  thus  a  series  of  phials 
showing  the  shades  of  color  which  those  various  solutions  are 
capable  of  producing.  To  ascertain  the  strength  of  an  un- 
known and  partially  exhausted  bleaching  liquor,  the  proof 
solution  of  iron  is  put  into  a  phial  similar  to  those  in  the  instru- 
ment, up  to  a  certain  mark,  ^th  of  the  whole.  The  phial  is 
then  filled  up  with  the  unknown  bleaching  liquor,  shaken,  and 
placed  beside  that  one  in  the  instrument  which  most  resembles 
it.  The  number  of  that  phial  is  its  strength  in  12ths  of  a 
degree  of  the  hydrometer;  and  by  inspecting  the  annexed 
table,  we  find  at  once  how  much  of  a  solution  of  bleaching 
powder,  which  is  always  kept  in  stock,  at  a  uniform  strengh  of 
6  degrees,  is  necessary  to  raise  the  whole  of  the  liquor  in  the 
steeping  vessel  to  the  desired  strength. 

"  The  instrument  is  formed  of  long  2-ounce  phials  cast  in 
a  mould;  those  of  blown  glass  not  being  of  uniform  diameter. 
The  outside,  which  alone  is  rough,  is  polished  by  grinding, 


88 


BLEACHING  POWDER. 


CO 

ft 


Fig.  8. 

a  42 

£5r  \J/fOi   UiUi   td}t=j?  &i 


and  in  this  state  they 
can  easily  be  procured 
at  4s.  6d.  a  dozen.  They 
are  placed  two  and  two, 
so  that  the  bottle  con- 
taining the  liquid  to  be 
examined  may  be  set 
by  the  side  of  any  one 
in  the  series,  and  the  color  compared  by  looking  through  the 
liquid  upon  a  broad  piece  of  white  paper  stretched  upon  a 
board  behind  the  instrument.* 

"To  explain  the  table,  it  is  necessary  to  state  that  the  steep- 
ing vessels  we  employ  contain  at  the  proper  height  for  receiving 
goods,  1440  gallons,  or  288  measures  of  5  gallons  each — a 
measure  being  the  quantity  easily  carried  at  a  time.  In  the 
following  table,  0  represents  water,  and  the  numbers  1,  2,  3, 
&c.,  are  the  strength  of  the  liquor  already  in  the  vessel  in  12ths 
of  a  degree  of  Twaddell,  as  ascertained  by  the  chlorimeter. 
If  the  vessel  has  to  be  set  anew,  we  see  by  the  first  table  that 
82  measures  of  liquor  at  6°  must  be  added  to  (256  measures  of) 
water  to  produce  288  measures  of  liquor  at  T85ths  of  a  degree. 
But  if  the  liquor  already  in  the  vessel  is  found  by  the  chlori- 
meter to  produce  a  color  equal  to  the  2d  phial,  then  24  mea- 
sures only  are  necessary,  and  so  on. 


To  stand  x82-° 

0  requires  32  measures. 

1  —  28  — 

2  —  24  — 

3  —  20  — 

4  —  16  — 

5  —  12  — 

6  —  8  — 

7  —  4  — 


To  stand  T45° 

0  requires  16  measures. 

1  —      12  — 

2  —       8  — 

3  —       4  — 


To  stand  /2° 

0  requires  24  measures. 

1  _     20  — 

2  —      16  — 

3  —     12  — 

4  —       8  — 

5  —       4  — 


To  stand  T%° 

0  requires  12  measures. 

1  —       8  — 

2  —       4  — 


*  The  above  figure  represents  the  instrument  fitted  with  tubes,  which  serve 
equally  well. 


BLEACH  INTG. 


89 


"Let  us  see  what  takes  place  on  mixing  chloride  of  lime 
with  protomuriate  of  iron.  On  the  old  view  of  the  constitu- 
tion of  bleaching  powder,  that  it  is  a  combination  of  chlorine 
and  lime,  we  have: — 

the  peroxide  of  iron  forming  a  peracetate  with  the  acetic  acid 
which  is  present.  Or,  supposing  with  Balard  that,  when  two 
atoms  of  chlorine  unite  with  two  atoms  of  lime,  the  product  is 
CaQl  +  CaO,  CIO,  we  have  this  formula  : — 

3  CaCl  ) 
3  (CaO,  CIO)  }  becoming  • 
12  FeCl  ) 

"Here,  one  third  only  of  the  iron  goes  to  form  the  deep- 
colored  peracetate,  while  the  whole  might  be  employed  for  that 
purpose,  by  using  protoacetate  instead  of  protochloride.  The 
latter,  however,  is  preferred,  from  the  greater  tendency  of  the 
acetate  to  attract  oxygen  from  the  air,  and  consequently  the 
greater  difficulty  of  preserving  it.  Even  with  the  chloride  it 
is  best  to  give  out  small  quantities  at  a  time,  preserving  the 
stock  in  well-closed  bottles." 

From  this  description,  it  will  be  seen  that  the  method  recom- 
mended by  Mr.  Crum,  may  be  adopted  for  testing  the  percentage 
of  the  powder  as  well  as  the  strength  of  the  liquors. 

To  return  to  the  bleaching  process.  The  goods  being  allowed 
to  steep  in  the  bleaching  liquor  for  some  hours,  they  are  lifted 
and  washed,  after  which,  if  they  are  thick  stout  goods,  they  are 
put  into  a  sour  for  a  little  while,  then  washed,  and  go  through 
the  same  operations  of  boiling,  liquoring,  and  souring  as  before; 
but,  for  all  common  fabrics,  we  have  found  it  the  best  practice 
to  sweeten*  the  goods  from  the  liquor,  hank  them  anew,  and  put 
them  back  into  a  new  liquor  of  the  same  strength  for  a  few 
hours,  wash  them  from  this,  and  allow  them  to  steep  for  an 
hour  in  strong  sour  of  vitriol  and  water,  about  1J  pint  of  the 
former  to  four  gallons  of  the  latter. 

There  is  perhaps  no  single  branch  connected  with  the  art  of 
dyeing  upon  which  there  is  more  difference  of  opinion  than 
bleaching.  Every  one  has  some  peculiarity  of  his  own;  but, 
when  the  peculiarities  are  all  compared,  the  difference  in  gene- 
ral is  only  nominal.  One  thing  may  be  noticed,  namety,  the 
necessity  of  washing  the  goods  well  from  the  liquor  before 


*  Building  the  goods  on  a  drainer,  and  pouring  water  upon  them  till  the 
water  ceases  to  taste  of  liquor  as  it  comes  from  them,  is  termed  sweetening. 


90 


BLEACHING. 


souring,  as  any  lime  remaining  upon  the  cloth  will  be  formed 
into  an  insoluble  sulphate,  and  resist  the  dye.  Some  maintain 
that  this  is  of  no  consequence;  in  our  opinion,  it  depends 
wholly  upon  the  color  which  is  to  be  dyed  on  the  cloth.  We 
have  found  that  light  pinks,  light  greens,  light  lavenders,  and 
sometimes  light  blues,  when  not  washed  well  from  the  liquor, 
were  often  full  of  white  spots,  which  we  ascribed  to  that  cause, 
although  there  are  white  spots  often  occurring  both  on  yarn 
and  cloth  from  other  causes;  but,  for  other  dark  shades,  we 
found  no  difference,  and  for  colors  to  be  dyed  with  the  bichro- 
mate of  potash  (chrome),  such  as  yellows,  ambers,  and  orange, 
we  seldom  gave  them  any  sour,  only  washed  from  the  first 
liquor  and  then  dyed  * 

Cotton  in  the  hank  (yarn),  when  it  is  to  be  finished  white, 
goes  through  the  same  process  as  cloth,  with  the  exception  of 
the  rot  steep;  but,  for  dyeing,  a  quicker  operation  is  adopted. 
All  cotton  yarn  must  be  boiled  in  water  for  three  or  four  hours 
previous  to  being  dyed.  Every  lot  of  ten-pounds'  weight,  con- 
stituting what  is  termed  a  bundle,  is  divided  into  six  equal 
numbers  of  spindles,  and  hung  upon  wooden  pins  about  three 
feet  long  and  two  inches  thick ;  this  is  termed  sticking. 

The  stock  liquor  for  yarn  is  generally  prepared  in  a  cask 
containing  about  120  gallons  of  water;  to  this  is  added  about 
20  lbs.  of  good  bleaching  powder,  stirred,  and  allowed  to  settle. 
A  small  tub,  of  a  size  in  which  a  bundle  is  wrought  freely, 
termed  a  ten-pound  tub,  is  filled  nearly  two-thirds  full  with 
boiling  water,  and  a  bucket  or  pailful  (about  four  gallons)  of 
the  stock  liquor  is  added.  The  bundle  is  now  let  down  as 
quickly  as  possible,  and  turned  over  for  about  ten  minutes, 
after  which  it  is  put  through  a  second  tub  of  the  same  size, 
with  water  made  a  little  sour  by  adding  about  an  imperial  gill 
of  vitriol.  It  is  wrought  in  this  for  about  five  minutes.  Being 
then  well  washed,  it  is  ready  to  be  dyed  of  almost  any  light 
shade.  By  this  method  two  men  can  bleach  and  wash  two 
hundred  pounds'  weight  of  yarn  in  about  three  hours,  a  quan- 
tity which,  by  the  other  process  of  boiling,  steeping,  and  sour- 
ing, would  have  occupied  two  days. 

Having  detailed  the  present  method  of  bleaching  cotton  goods 
for  dyeing,  we  may  say  a  little  upon  the  chemical  nature  of 
these  processes.  Previous  to  the  discovery  of  the  elementary 
nature  of  chlorine,  when  that  substance  was  considered  a  com- 
pound of  muriatic  acid  and  oxygen,  it  was  thought  that  the 

*  In  souring  fine  goods,  the  vessel  used  is  of  consequence.  In  using  a 
vessel  lined  with  lead,  there  was  experienced  for  a  long  time  a  constant 
occurrence  of  small  holes  in  the  goods.  On  changing  the  vessel  for  a  wooden 
one,  this  evil  has  entirely  disappeared.  The  cause  of  the  holes  has  not,  how- 
ever, been  determined. 


BLEACHING. 


91 


acid  parted  with  its  oxygen,  and  that  this  constituent  bleached 
the  goods  in  the  same  way  as  atmospheric  air  in  croft  bleaching, 
but  more  rapidly.  When  the  true  nature  of  chlorine  was  dis- 
covered, the  theory  was  somewhat  changed;  finding,  as  was 
then  supposed,  that  chlorine  did  not  bleach  except  water  was 
present,  it  was  considered  that  the  chlorine  united  with  the 
hydrogen  of  the  water  forming  muriatic  acid,  and  that  the 
liberated  oxygen  was  still  the  bleaching  agent. 

This  theory  is  still  maintained  and  supported  by  various 
analogies.  We  quote  the  following  from  Gregory  and  Liebig's 
edition  of  Turner's  Chemistry:  "One  of  the  most  important 
properties  of  chlorine  is  its  bleaching  power.  All  animal  and 
vegetable  colors  are  speedily  removed  by  chlorine,  and  when 
the  color  is  once  destroyed  it  can  never  be  restored.  Davy 
proved  that  chlorine  cannot  bleach  except  water  be  present ; 
thus  dry  litmus  paper  suffers  no  change  in  dry  chlorine,  but 
when  water  is  admitted,  the  color  speedily  disappears.  It  is 
well  known  also,  that  hydrochloric  acid  (muriatic  acid)  is 
always  generated  when  chlorine  bleaches.  From  these  facts, 
it  is  inferred  that  water  is  decomposed  during  the  process,  that 
its  hydrogen  unites  with  chlorine,  and  that  decomposition  of 
the  coloring  matter  is  occasioned  by  the  oxygen  liberated.  The 
bleaching  property  of  binoxide  of  hydrogen,  and  of  chromic 
and  permanganic  acids,  of  which  oxygen  is  certainly  the  decol- 
oring principle,  leaves  little  doubt  of  the  accuracy  of  the  fore- 
going explanation." 

Another  theory  has  been  advanced,  and  equally  if  not  more 
tenable,  by  which  the  chlorine  is  supposed  to  act  directly  upon 
the  coloring  matter.  The  following  is  from  Sir  Robert  Kane's 
Treatise  on  Chemistry ;  "  Formerly,  it  was  considered  that  water 
was  necessary  for  this  bleaching,  and  that  the  chlorine  combined 
with  the  hydrogen,  while  the  oxygen  of  the  water  being  thus 
thrown  upon  the  organic  substance,  oxidized  it,  and  formed  a 
new  body,  which  was  colorless.  I  have  shown,  however,  that 
this  is  not  the  case,  but  that  the  chlorine  enters  into  the  constitu- 
tion of  the  new  substance  formed,  sometimes  replacing  hydrogen, 
at  others  simply  combining  with  the  colored  body,  and  in  some, 
the  reaction  being  so  complete  that  its  immediate  stages  cannot 
be  completely  traced." 

This  theory  is  also  supported  by  several  analogies,  such  as 
the  action  of  chlorine  upon  indigo,  already  noticed  ;  but  which 
of  the  changes,  alluded  to  by  Sir  Eobert  Kane,  takes  place 
during  the  bleaching  of  cotton,  is  not  yet  known.  Chloride  of 
lime,  says  the  same  author,  does  not  bleach  except  an  acid  be 
present  to  combine  with  the  lime,  and  set  the  chlorine  at 
liberty  ;  but  this  is  only  conditional.  It  is  true  that  if  blue 
litmus  paper  be  put  into  a  solution  of  newly  dissolved  chloride 


92 


BLEACHING. 


of  lime,  it  is  not  bleached;  but  if  the  solution  be  allowed  to 
remain  in  contact  with  the  air  for  an  hour  or  two,  the  lime 
combines  with  the  carbonic  acid  of  the  atmosphere;  and  if  the 
blue  litmus  paper  be  put  into  .this  solution,  it  is  instantly 
bleached  by  the  liberated  chlorine.  Cotton  that  has  not  been 
boiled  in  alkalies,  is  acted  upon  as  the  litmus  paper  in  both 
cases  ;  but  if  the  cotton  has  received  a  good  alkaline  boil,  and 
is  well  washed,  the  bleaching  process  goes  on,  although  the 
bleaching  powder  be  newly  dissolved.  This  shows  that  the 
alkaline  lyes  effect  a  change  upon  the  coloring  matter.  The 
nature  of  this  change,  we  are  not  as  yet  prepared  to  state ; 
several  opinions  have  been  given,  but  they  are  hypothetical, 
and  some  of  them  are  not  borne  out  by  practice.  Neither  is 
the  theory  of  Sir  Eobert  Kane,  of  the  formation  during 
bleaching  of  a  colorless  chloride,  or  oxide,  at  all  admissible,  at 
least  as  regards  cotton.  According  to  this  theory,  goods  being 
bleached  by  having  formed  upon  them  a  new  compound,  would 
become  heavier,  whereas  practice  shows  that  the  operation  of 
bleaching  causes  the  goods  to  lose  about  3  per  cent,  in  weight. 
From  several  experiments  which  we  made,  we  found  that  the 
loss  by  boiling  was  5  per  cent.,  and  by  bleaching,  3  per  cent., 
in  all  8  per  cent. 

Whenever  the  cloth  is  put  into  the  bleaching  liquor,  there 
are  acids  formed,  the  principal  of  which  is  the  hydrochloric; 
but  whether  it  is  from  the  chlorine  combining  with  the  hydro- 
gen of  the  water,  or  the  coloring  matter  of  the  goods,  we  cannot 
say,  the  latter  we  think  most  probable.  Our  opinion  is,  that 
the  chlorine  combines  with  the  hydrogen  of  the  coloring 
matter;  and,  according  to  a  law  we  have  several  times  alluded 
to,  the  remaining  elements  of  the  coloring  matter  form  a  new 
substance,  which  is  soluble,  and  thus  the  whole  coloring  matter 
is  taken  off  the  cloth.  In  vats,  where  several  hundred  pounds' 
weight  of  cotton  have  been  bleached  before  changing  the  liquor, 
there  is  evidence  of  more  substances  remaining  than  merely  a 
solution  of  muriate  of  lime;  but  what  these  are,  we  dare  not  as 
yet  venture  to  assert. 

The  effect  of  light  in  the  operation  of  bleaching  also  favors 
this  hypothesis,  for  we  know  that  exposure  to  the  sun  facilitates 
the  process  very  much.  This  circumstance,  however,  tells  in 
favor  of  the  theory  that  the  oxygen  is  the  bleaching  agent,  as 
well  as  in  favor  of  the  theory  which  makes  the  chlorine  the 
bleaching  agent.  There  is  only  this  difficulty,  which,  how- 
ever, must  not  be  overlooked,  namely,  that  if  a  solution  con- 
taining chlorine  is  exposed' to  the  light,  there  is  a  decomposi- 
tion of  the  water;  for  the  chlorine  combines  with  the  hydrogen, 
and  liberates  the  oxygen  of  the  aqueous  molecule.  The  oxygen 
would  again,  by  this  theory,  require  to  combine  with  the 


SULPHUR. 


93 


hydrogen  of  the  coloring  matter,  and  form  water,  a  series  of 
affinities  which  we  cannot  conceive ;  for  if  the  affinity  of  the 
chlorine  be  stronger  for  the  hydrogen  than  for  the  oxygen  of 
the  water,  it  would  necessarily  take  the  hydrogen  from  the 
coloring  matter,  seeing  that  oxygen,  which  by  this  showing 
has  the  weaker  power,  decomposes  it  to  form  water  again,  a 
series  of  reactions  altogether  irreconcilable  with  one  another. 
That  the  oxygen  combines  with  the  color,  forming  a  colorless 
oxide,  is  quite  irreconcilable  with  the  practical  fact  of  the 
goods  losing  weight  by  bleaching. 

Such  is  an  outline  of  the  processes  of  bleaching  cotton  goods 
for*  dyeing,  as  practised  in  most  dye-works  at  the  present  day. 
Woollen  and  silk  are  bleached  by  exposing  them,  after  being 
boiled  or  scoured,  to  the  vapor  of  sulphurous  acid,  which  pro- 
cess will  be  noticed  under  sulphur;  but  they  are  not  thus 
bleached  for  dyeing. 

Ozone. — Within  a  few  years  a  substance,  or  property,  which 
has  got  the  name  of  Ozone,  has  been  discovered  to  have 
extraordinary  bleaching  properties.  If  a  few  sticks  of  phos- 
phorus be  placed  in  a  large  bottle  containing  a  little  water  at 
bottom,  and  corked,  in  a  short  time  the  atmosphere  of  the 
bottle  is  found  to  possess  peculiar  properties,  and  is  said  to 
contain  ozone,  and  acts  in  relation  to  a  great  many  substances 
the  same  part  as  chlorine.  Professor  C.  F.  Schonbein,  the 
discoverer  of  this  substance,  and  who  has  made  it  the  subject 
of  careful  investigation,  was  able  to  bleach,  or  decolor,  sulphate 
of  indigo,  and  also  many  flowers  by  means  of  it.  The  real 
character  of  ozone  is  as  yet  only  imperfectly  understood.  The 
discoverer  supposes  it  to  be  a  volatile  peroxide  of  hydrogen  ; 
and  this  idea  has  been  to  some  extent  verified  by  experiments, 
while  others  suppose  it  to  be  a  new  condition  of  oxygen.  How- 
ever, enough  is  known  of  it  to  induce  us  to  think  that  when 
easy  methods  of  producing  and  applying  it  are  discovered, 
ozone  will  be  found  of  much  value  in  the  arts. 


Sulphur  (S.  16). 

Sulphur  has  been  known  from  the  earliest  ages.  It  is  found 
in  large  quantities,  uncombined  in  the  neighborhood  of  vol- 
canoes ;  and  is  also  extensively  diffused  through  nature  in  com- 
bination, especially  with  metals.  It  is  obtained  in  great  abund- 
ance by  roasting  the  sulphurets  of  iron,  lead,  copper,  and  zinc. 

Sulphur  is  a  hard,  brittle  substance,  of  a  greenish-yellow 
color.  It  is  not  soluble  in  water,  and  is  not  changed  by  ex- 
posure to  the  air.  When  heated  to  the  temperature  of  824° 
Fah.,  it  sublimes,  and  deposits  again  in  the  fine  powder  well 


94 


SULPHUROUS  ACID. 


known  as  the  flowers  of  sulphur.  If  heated  in  a  close  vessel, 
say  a  glass  flask,  to  218°  Fah.  it  melts  and  becomes  liquid  as 
water,  but  by  increasing  the  heat  it  undergoes  some  curious 
changes;  at  340°  it  begins  to  get  thick,  and  assumes  a  reddish 
color,  and  if  the  heat  be  continued,  it  becomes  so  thick  that  it 
will  not  pour  from  the  vessel.  At  482°  it  begins  to  become 
thinner,  and  continues  thinning  until  it  boils  at  750°.  When 
suddenly  cooled  from  its  most  fluid  state,  which  is  about  224°, 
by  throwing  it  into  cold  water,  it  becomes  instantly  brittle; 
but  if  cooled  in  the  same  manner,  when  thick  (about  400°),  it 
remains  quite  soft,  and  may  be  drawn  into  threads.  If  heated 
in  the  open  air  to  about  300°  it  takes  fire,  and  burns  with  a 
pale  blue  flame,  and  gives  off  most  suffocating  fumes  of  sulphur- 
ous acid  gas. 

Sulphur  combines  with  oxygen  in  several  proportions, 
forming  acids  of  considerable  importance  in  the  arts.  These 
are : — 

Sulphurous  acid  S02 

Sulphuric  acid   S03  Anhydrous 

Hyposulphurous  acid  .  .  .  S2  02 
Hyposulphuric  acid  .    .    .    .    S2  05 

Sulphurous  Acid  is  a  gaseous  substance,  and  is  always 
produced  when  sulphur  is  burned  in  the  air,  or  in  oxygen.  It 
may  be  prepared  also  from  the  compounds  of  sulphur.  If 
sulphuric  acid  be  heated  in  contact  with  metallic  copper,  or 
charcoal,  sulphurous  acid  is  given  off.    We  have  : — 

2  S04  H  and  Cu  =  S04  Cu  +  S02  +  2  HO 

If  charcoal  be  used  instead  of  copper  in  this  experiment,  car- 
bonic gas  is  also  liberated.  It  may  also  be  prepared  by  heating 
together  3  parts  flowers  of  sulphur,  and  4  parts  black  oxide  of 
manganese,  in  a  similar  apparatus  to  that  described  for  the  pre- 
paration of  oxygen  from  manganese. 

This  gaseous  acid,  as  has  been  stated,  is  much  used  in 
bleaching  animal  substances,  as  silk  and  woollen ;  and  also 
some  vegetable  substances,  as  straw.  For  these  operations 
the  gas  is  procured  by  merely  burning  the  sulphur  in  the  air. 
The  articles  to  be  bleached  are  put  into  a  chamber,  or  box, 
made  as  tight  as  possible,  in  which  is  placed  a  small  pan  of 
sulphur,  which  is  kindled  by  putting  into  it  a  piece  of  redhot 
iron.  The  chamber  is  then  closed,  and  the  articles,  damp 
and  well  spread  out,  are  thus  exposed  to  the  sulphurous 
fumes.  The  gas  is  absorbed  in  the  first  place,  by  the  water 
on  the  goods,  and  is  thus  brought  into  immediate  contact, 
and  enabled  to  combine  with  the  fabric.  Goods  bleached  by 
this  gas  are  increased  in  weight,  showing  a  combination;  they 


SULPHURIC  ACID. 


95 


are  not  permanently  white,  showing  that  the  compound  formed 
is  decomposed;  indeed,  the  gas  gradually  escapes,  and  by  im- 
mersing the  goods  in  a  stronger  acid,  the  white  compound  is 
decomposed.  This  may  be  beautifully  illustrated  by  exposing 
a  red  rose  to  the  fumes  of  sulphurous  acid  gas ;  it  is  bleached 
white,  but  by  putting  it  into  a  sour  (vitriol  and  water),  the  red 
color  is  restored.  This  shows  the  distinctive  characters  of  this 
gas  and  chlorine,  as  bleaching  agents,  and  that  any  analogy 
drawn  between  them  to  support  a  theory  is  groundless.  Some 
bleachers  of  woollen  pass  the  goods  through  a  solution  of 
sulphurous  acid  in  water,  instead  of  stoving  them.  Bleaching 
by  this  gas  is  not  done  with  goods  that  are  to  be  dyed. 

Sulphurous  acid  passes  readily  into  sulphuric  acid  by  ab- 
sorbing more  oxygen.  In  newly  distilled  water,  or  water 
having  no  air  or  oxygen  dissolved  in  it,  sulphurous  gas  may 
be  kept  a  long  time  if  well  corked  up,  but  without  these  pre- 
cautions it  very  soon  combines  with  the  oxygen  dissolved  in 
the  water.  If  a  quantity  of  peroxide  of  iron  is  put  into  a  solu- 
tion of  this  gas,  it  passes  into  the  state  of  sulphuric  acid,  and 
protoxide  of  iron.    The  formula  is 

Fe2  03+S02=S04  Fe  +  FeO 

Sulphuric  Acid  is  one  of  the  most  important  of  the  com- 
pounds of  sulphur;  it  is  not  produced  by  the  direct  action  of 
its  elements,  but  generally  from  the  oxidation  of  sulphurous 
acid.  We  mentioned,  when  treating  of  nitrogen  (page  60), 
that  the  binoxide  of  nitrogen  on  coming  into  contact  with  the 
air  combines  with  more  oxygen,  and  is  converted  into  the 
peroxide  of  nitrogen;  and  that  this  compound  readily  yields 
its  oxygen  again  toother  bodies  which  have  a  strong  attraction 
for  it.  If  sulphurous  acid  is  brought  into  contact  with  peroxide 
of  nitrogen  in  the  presence  of  water,  a  decomposition  takes 
place,  and  there  is  formed  sulphuric  acid  and  nitrous  acid, 
which  may  be  represented  by  the  formula, 

S02+N04=S03  +  N03 

One  proportion  of   >  gQ  Crystalline  sulphuric  acid. 

sulphurous  acid  i 


One  proportion  of 
peroxide  nitrogen. 


Nitrous  acid. 


Both  of  these  compounds  when  formed  are  taken  up  by  the 
water,  the  first  forming  hydrous  sulphuric  acid,  the  second  is 
decomposed,  every  three  proportions  being  resolved  into 
3  N03=2  NO,  +  N05 


96 


SULPHURIC  ACID. 


(NO.- 

3  proportions  of  0... 
nitrous  acid,  N03  is   <  N03 
resolved  into  0 ... 


n6; 


Binoxide  of  nitrogen. 


Binoxide  of  nitrogen. 


Nitric  acid. 


The  nitric  acid  remains  in  the  water  with  the  vitriol,  but  the 
binoxide  of  nitrogen  rises  to  the  surface  and  imbibes  oxygen, 
and  is  again  converted  into  peroxide,  ready  to  undergo  again 
the  same  changes.  On  the  large  scale,  these  changes  and  re- 
actions are  brought  about  by  causing  the  sulphurous  acid  fumes 
from  burning  sulphur,  and  the  peroxide  of  nitrogen  fumes 
from  pouring  sulphuric  acid  upon  nitrate  of  soda  or  potash,  to 
pass  together  into  large  leaden  chambers  along  with  a  jet  of 
steam.  In  this  chamber  the  reactions  above  described  go  on. 
At  the  bottom  of  this  chamber  is  a  layer  of  water  for  absorbing 
the  acids  formed ;  and  at  the  top  is  an  aperture  to  admit  the 
air  and  the  other  gases,  so  that  the  binoxide  of  nitrogen  becomes 
peroxidized  as  it  rises  to  the  top.  The  water  from  the  bottom 
is  drawn  off  at  short  intervals  as  it  becomes  impregnated  with 
the  acid.  These  intervals  are  so  arranged  that  the  specific 
gravity  of  the  acid  when  drawn  off  is  about  1.600=120°  T wad- 
dell.  It  is  then  evaporated  in  leaden  tanks,  until  the  specific 
gravity  becomes  about  1.76,  or  152°  Twaddell.  If  the  operation 
were  continued  farther,  the  acid  would  act  upon  the  lead ;  it  is 
consequently  transferred  to  vessels  of  glass  or  platinum,  and 
evaporated  until  the  specific  gravity  rises  to  about  1.847,  or 
169i  Twaddell. 

The  whole  of  the  operation  of  making  sulphuric  acid  may  be 
done,  for  illustration,  by  the  simple  apparatus  on  next  page. 
Generate  sulphurous  acid  S02,  in  one  bottle  (B),  and  peroxide 
of  nitrogen  N04  in  another  (C),  and  cause  the  two  gases  to 
meet  in  a  third  bottle  (A),  having  a  little  water  at  bottom  ;  the 
formation  of  sulphuric  acid  will  go  on  as  described,  and  be  found 
in  the  water  of  the  condensing  vessel  (A)  after  the  operation. 

A  great  quantity  of  sulphuric  acid  is  made  by  burning  iron 
pyrites,  a  native  compound  of  iron  and  sulphur.  This  mineral 
often  contains  arsenic,  which  the  sulphurous  acid  carries  with 
it  into  the  acid  chamber  ;  and  therefore  the  vitriol  made  from 
this  source  contains  arsenic  as  an  impurity. 

Sulphuric  acid  may  also  be  prepared  by  putting  a  quantity 
of  sulphate  of  iron  into  an  earthenware  retort,  and  applying  a 
strong  heat  to  it ;  the  sulphuric  acid  is  distilled  over,  and 
peroxide  of  iron  remains.  This  is  the  oldest  method  of  obtain- 
ing sulphuric  acid,  and  is  still  practised  in  some  parts  of 
Germany.  The  acid  so  obtained  is  very  strong;  has  a  dark 
color,  and  gives  oft*  a  quantity  of  white  fumes  ;  hence  it  is  called 
fuming  sulphuric  acid.    It  is  also  called  Nordhausen  acid,  from 


SULPHURIC  ACID.  97 


Fig.  9. 


its  being  manufactured  there.  When  this  acid  is  poured  into 
cold  water,  it  produces  a  hissing  noise,  like  that  produced  by 
putting  a  redhot  iron  into  water.  This  acid  is  excellently 
adapted  for  making  sulphate  of  indigo. 

Sulphuric  acid  may  be  mixed  with  water  in  any  proportion, 
but  there  seem  to  be  certain  definite  quantities  with  which  it 
will  combine  with  water  chemically.  When  added  to  water, 
there  is  always  heat  evolved;  this  heat  is  a  definite  quantity, 
and  accompanied  by  a  condensation  of  bulk,  as  the  dyer  may 
easily  convince  himself  by  taking  measured  quantities  of  strong 
vitriol  and  water,  and  mixing  them;  when  the  mixture  is  cool, 
he  will  find  a  considerable  diminution  of  bulk.  The  following 
experiments  upon  the  amount  of  condensation,  and  heat  given 
out,  were  performed  with  a  common  alkali  meter  and  thermo- 
meter : — 


Measure  of 
water. 

Measure  of 
Acid. 

Heat  when 
mixed. 

Increase  of 
heat. 

Loss  by  conden- 
sation. 

90 

10 

86° 

40° 

5 

80 

20 

116 

70 

7 

70 

30 

154 

108 

8 

60 

40 

188 

142 

9J 

50 

50 

210 

164 

11 

40 

60 

212 

166 

11 

30 

70 

200 

154 

9 

20 

80 

164 

118 

8i 

10 

90 

136 

90 

7 

7 


98 


SULPHURIC  ACID. 


The  above  is  the  mean  of  three  trials.  The  proportions  of 
acid  and  water  were  taken  to  make  100  graduations,  and  mixed. 
The  heat  was  observed  immediately  after  mixing,  and  the  mix- 
ture was  kept  in  a  stoppered  bottle  until  cold,  when  it  was 
measured  by  the  alkalimeter,  and  the  loss  by  condensation 
noted.  The  heat  of  the  water  and  acid  separately  was  46°. 
The  acid  used  was  specific  gravity  1.795,  taken  by  Twaddell, 
179°.  Another  proof  that  water  and  sulphuric  acid  form  a 
definite  compound,  is,  that  when  the  acid  has  the  specific  gra- 
vity of  1.78,  the  composition  is  S04H  +  HO.  This,  at  a  tem- 
perature of  32°,  will  crystallize  in  large  and  regular  crystals, 
while  stronger  or  weaker  acid,  at  the  same  temperature,  will 
not  crystallize.  This  is  a  circumstance  sometimes  experienced 
in  the  dye-house,  and  is  commonly  taken  as  an  evidence  of 
impurity  in  the  acid,  which,  however,  it  is  not. 

The  ordinary  impurities  in  sulphuric  acid  are  lead,  nitric 
acid,  arsenic,  and  sometimes  sulphate  of  potash,  which  is  added 
to  give  it  density.  The  presence  of  lead  is  easily  detected  by 
diluting  a  little  of  the  acid  with  distilled  water  ;  sulphate  of 
lead  is  not  soluble  in  dilute  acid,  and  when  present  there  is 
produced  a  milkiness  in  the  solution,  as  is  often  seen  in  the 
dye  house  when  the  acid  is  added  to  water.  Nitric  acid  may  be 
detected,  as  described,  page  66,  by  suspending  a  clean  crystal 
of  sulphate  of  iron  in  the  acid,  and  heating  it ;  a  black  ring  is 
then  seen,  or  the  smell  of  peroxide  of  nitrogen  perceived. 
Sometimes,  a  little  of  this  peroxide  is  present  in  the  acid,  and 
either  of  these  impurities  is  very  bad  when  the  sulphuric  acid 
is  to  be  used  for  indigo,  garancine,  or  any  organic  substance. 
Arsenic  may  be  detected  by  diluting  the  acid,  and  passing  a 
current  of  sulphureted  hydrogen  through  it,  which  gives  a 
yellow  precipitate  when  arsenic  is  present.  This  substance, 
however,  is  not  deleterious  in  those  operations  of  the  dye-house 
wherein  sulphuric  acid  is  used.  Sulphate  of  potash,  or  soda, 
may  be  detected  by  putting  a  few  drops  of  acid  into  a  small 
basin,  and  saturating  it  with  ammonia,  then  evaporating  to  dry- 
ness, and  continuing  a  strong  heat  until  all  white  fumes  of  sul- 
phate of  ammonia  cease;  nothing  will  remain  if  the  acid  is 
pure. 

After  ascertaining  that  the  acid  is  pure,  the  hydrometer 
may  be  used  to  discover  its  strength.  The  following  t^ble  will 
be  useful  in  this  operation  : — 


SULPHURIC  ACID,  99 


Liquid, 
acid. 

specific  gravity. 

Dry  acid  oO«j  in 
100  parts. 

.Liquid 
acid. 

specific  gravity. 

Dry  acid  feOg  in. 
100  parts. 

100 

1.8485 

81.54 

50 

1.3884 

40.77 

99 

1.8475 

80.72 

49 

1.3788 

39.95 

98 

1.8460 

79.90 

48 

1.3697 

39.14 

97 

1.8430 

79.09 

47 

1.3612 

38.32 

96 

1.8400 

78.28 

46 

1.3530 

37.51 

95 

1.8376 

77.46 

45 

1.3440 

36.59 

94 

1.8336 

76.65 

44 

1.3345 

35.88 

93 

1.8290 

75.83 

43 

1.3255 

35.06 

92 

1.8233 

75.02 

42 

1.3165 

34.25 

91 

1.8179 

74.20 

41 

1.3080 

33.43 

90 

1.8115 

73.39 

40 

1.2999 

32.61 

89  » 

1.8043 

72.57 

39 

1.2913 

31.80 

88 

1.7962 

71.75 

38 

1.2826 

30.98 

87 

1.7850 

70.94 

37 

1.2740 

30.17 

86 

1.7774 

70.12 

36 

1.2654 

29.35 

85 

1.7673 

69.31 

35 

1.2572 

28.54 

84 

1.7570 

68.49 

34 

1.2490 

27.72 

83 

1.7465 

67.68 

33 

1.2409 

26.91 

82 

1.7300 

66.86 

32 

1.2334 

26.09 

81 

1.7245 

66.05 

31 

1.2260 

25.28 

80 

1.7120 

65.23 

30 

1.2184 

24.46 

79 

1.6993 

64.42 

29 

1.2108 

23.65 

78 

1.6870 

63.62 

28 

1.2030 

22.83 

77 

1.6750 

62.78 

27 

1.1956 

22.01 

76 

1.6630 

61.97 

26 

1.1876 

21.20 

75 

1.6520 

61.15 

25 

1.1792 

20.38 

74 

1.6415 

60.34 

24 

1.1706 

19.57 

73 

1.6321 

59.52 

23 

1.1626 

18.75 

72 

1.6204 

58.71 

22 

1.1549 

17.94 

71 

1.6090 

57.89 

21 

1.1480 

17.12 

70 

1.5975 

57.08 

20 

1.1410 

16.31 

69 

1.5868 

56.26 

19 

1.1330 

15.49 

68 

1.5760 

55.45 

18 

1.1246 

14.68 

67 

1.5648 

54.63 

17 

1.1165 

13.86 

66 

1.5503 

53.82 

16 

1.1090 

13.05 

65 

1.5390 

53.00 

15 

1.1019 

12.23 

64 

1.5280 

52.18 

14 

1.0953 

11.41 

63 

1.5170 

51.87 

13 

1.0887 

10.60 

62 

1.5066 

50.55 

12 

1.0809 

9.78 

61 

1.4960 

49.74 

11 

1.0743 

8.97 

60 

1.4860 

48.92 

10 

1.0682 

8.15 

59 

1.4760 

48.11 

9 

1.0614 

7.34 

58 

1.4660 

47.29 

8 

1,0544 

6.52 

57 

1.4560 

46.48 

7 

1.0477 

5.71 

56 

1.4460 

45.66 

6 

1.0405 

4.89 

55 

1.4360 

44.85 

5 

1.0336 

4.08 

54 

1.4265 

44.03 

4 

1.0268 

3.26 

53 

1.4170 

43.22 

3 

1.0206 

2.45 

52 

1.4073 

42.40 

2 

1.0140 

1.63 

51 

1.3977 

41.58 

1 

1.0074 

0.82 

The  presence  of  sulphuric  acid  is  detected  by  adding  to  any 
compound  in  solution  a  salt  of  barium,  which  gives  a  white 
precipitate  not  soluble  in  nitric  acid.    Sulphuric  acid  has  a 


100 


HYPOSULPHUROUS  ACID. 


strong  attraction  for  water,  so  much  so,  that  if  left  exposed  to 
the  atmosphere,  it"  will  absorb  moisture  and  become  dilute.  A 
saucer  half-filled  with  strong  sulphuric  acid  will  become  full 
in  a  few  days  by  exposure  to  the  atmosphere  of  a  dye-house. 
This  shows  the  evil  of  leaving  the  stoppers  out  of  the  bottles, 
or,  as  is  often  the  case,  leaving  quantities  of  this  acid  in  an 
open  jug.  Animal  and  vegetable  substances  put  into  sulphuric 
acid  become  charred  ;  the  hydrogen  and  oxygen  of  these  bodies 
go  to  form  water,  which  combines  with  the  acid,  and  the  car- 
bon is  left  as  charcoal ;  this  is  the  effect  it  produces  upon  the 
skin.  The  presence  of  these  matters  also  tends  to  weaken  the 
acid,  and  should  therefore  be  avoided  as  much  as  possible. 
This  may  be  the  proper  place  to  refer  to  a  bad  practice  we 
have  seen  in  the  dye-house.  When  using  vitriol,  the  jug  con- 
taining it  is  often  placed  upon  the  floor  for  convenience;  and  a 
workman  passing  that  way  comes  against  it  with  his  foot,  and 
not  only  spills  the  acid,  but  occasionally  his  shoe  is  filled  with 
it.  When  this  happens,  the  first  impulse,  which  is  often 
obeyed,  is  to  plunge  the  foot  into  water,  when,  of  course,  the 
mixture  of  vitriol  and  water  in  the  shoe  is  brought  nearly  to 
the  boiling  point,  as  may*  be  learned  from  the  table  above. 
Severe  accidents  by  this  reckless  habit  are  not  uncommon. 
When  such  an  accident  does  take  place,  the  person  ought  to 
take  off  his  shoe  and  stocking  before  putting  his  foot  in  water ; 
and  if  his  foot  has  been  previously  dry,  or  merely  moist,  he 
will  escape  unhurt.  The  hand,  if  dry,  may  be  kept  in  strong 
vitriol  for  some  time,  without  burning,  but  very  shortly  the 
acid  begins  to  decompose  the  skin,  and  then  pain  is  felt. 

Hyposulphurous  Acid. — This  acid  is  of  singular  compo- 
sition; although  it  is  composed  of  equal  equivalents  of  sulphur 
and  oxygen,  what  might  be  termed  SO,  yet  it  is  represented 
double  S20o.  This  seeming  anomaly  is  got  over  by  supposing 
it  to  be  a  compound  of  sulphurous  acid  with  sulphur,  thus  : 
S02  +  S.  This  acid  is  not  prepared  directly  from  its  elements, 
but  is  formed  either  in  combination  as  a  salt,  or  by  double  de- 
composition. If  a  current  of  sulphurous  acid  gas  S02,  and 
sulphureted  hydrogen  gas  SH,  are  passed  through  water  to- 
gether, four  parts  or  equivalents  of  the  former,  and  two  parts 
or  equivalents  of  the  latter  combine  to  form  three  equivalents 
of  hyposulphurous  acid,  and  two  of  water.  The  formula  may 
be  accordingly  this:  4S02  and  2SH  =  3S202+2HO.  The 
acid,  when  uncombined,  is  very  unstable  ;  after  exposure  for  a 
short  time  it  deposits  sulphur,  and  sulphurous  acid  remains. 

When  a  solution  of  soda  or  potash  is  boiled  with  sulphur, 
there  is  formed  in  the  liquid  hyposulphate,  and  sulphuret,  of 


SULPHURETED  HYDROGEN. 


101 


the  base,  supposing  that  soda  is  employed ;  then  four  propor- 
tions of  sulphur,  and  three  of  soda,  produce 

One  hyposulphite  of  soda  NaO  S202,  and 
Two  sulphuret  of  sodium  2NaS. 

The  hyposulphites  are  not  yet  much  used  in  dyeing;  but  from 
the  property  which  the  alkaline  salts  of  this  acid  has  of  dis- 
solving many  metallic  oxides,  it  might  undoubtedly  be  advan- 
tageously applied  for  several  purposes. 

Hyposulphuric  Acid. — This  acid  is  easily  formed  in  com- 
bination by  passing  a  current  of  sulphurous  acid  through  water 
in  which  is  diffused  a  quantity  of  black  oxide  of  manganese; 
two  proportions  of  the  acid  combine  with  one  proportion  of 
oxygen  from  the  manganese,  and  form  the  hyposulphuric  acid, 
which  combines  with  the  remaining  manganese  to  form  the 
hyposulphate  of  manganese  :— 

Mn022S02  =  MnO  S205. 

This  acid  may  be  "obtained  free  from  the  manganese  by  pre- 
cipitating that  metal,  but  cannot  be  freed  from  water.  Its 
hydrate  is  moreover  very  unstable,  but  in  union  with  bases  it 
forms  salts  of  great  stability. 

Sulphureted  Hydrogen. — Sulphur  combines  with  hydro- 
gen in  equal  equivalents,  and  forms  a  gaseous  compound 
very  useful  as  a  test — this  is  sulphureted  hydrogen,  or  sul- 
phide of  hydrogen,  which  is  not  inappropriately  termed  hydro- 
sulphuric  acid,  as  the  gas  has  acid  properties.  This  gas  is  pre- 
pared by  acting  upon  a  metallic  sulphuret,  with  an  acid  in  this 
manner :  A  few  pieces  of  protosulphuret  of  iron  are  put  into 
a  glass  or  porcelain  vessel  containing  a  little  water,  and  a  small 
quantity  of  sulphuric  or  hydrochloric  acid  is  added ;  a  gas  of 
a  strong  suffocating  smell  immediately  begins  to  come  off, 
which  is  sulphureted  hydrogen.  The  reaction  which  takes 
place  is  as  follows : — 

Sulphuret  of  Iron,  {|e"^^^  Sulphide  °f  h^m- 
Sulphuric  acid,       {gj-  Sulphate  of  iron. 

This  gas  is  absorbed  by  water,  and  is  sometimes  used  in 
solution  as  a  test.  It  is  also  taken  up  in  great  quantity  by  a 
solution  of  ammonia,  forming  hydrosulphuret  of  ammonia, 
also  much  used  as  a  test.  When  used  for  this  purpose  in 
the  gaseous  state,  such  an  apparatus  as  the  accompanying 


102 


SULPHUBETED  HYDKOGEN. 


will  serve.  The  sulphuret  of  iron 
or  other  sulphuret,  is  put  into  the 
bottle  «,  containing  some  water,  and 
the  acid  is  added  by  the  long  fun- 
nel d.  The  gas  escapes  by  the 
tube  e,  /,  and  passes  through  the 
solution  to  be  tested,  contained  in 
the  glass  g.  The  same  apparatus 
serves  for  passing  the  gas  through 
water  or  liquid  ammonia,  when  it 
is  required  to  produce  a  saturated 
solution.  The  precipitates  formed 
by  passing  this  gas  through  solu- 
tions of  various  substances  are  very 
characteristic.  Thus,  a  solution  • 
containing — 

Antimony  produces  .    .    .  Orange  precipitate. 

Tin  and  arsenic    ....  Yellow  precipitate. 

Manganese   Flesh-red  precipitate. 

Zinc   White  precipitate. 

Lead,  copper,  iron,  &c.  .    .  Black  precipitate. 

Sometimes,  however,  it  is  necessary  to  add  a  little  ammonia 
before  these  results  are  obtained. 

Sulphureted  hydrogen  is  evolved  from  decaying  animal  and 
vegetable  matters,  and  from  dunghills,  common  sewers,  and 
putrefying  bodies  that  contain  sulphur.  It  is  very  deleterious 
to  health,  and  care  should  be  taken  to  avoid  breathing  it.  The 
effect  of  this  gas  upon  many  dyes  is  so  very  great  that  the 
slightest  quantity  in  the  atmosphere  is  hurtful.  It  gives  to 
chrome  yellows  and  oranges  a  smoky  appearance,  which  can- 
not be  removed ;  and  to  spirit  reds  it  gives  a  rusty  brown 
appearance.  Wherever,  indeed,  there  is  a  metal  present  in  the 
dye,  this  gas  affects  the  color.  Sulphur  does  so  also;  conse- 
quently the  same  effects  are  often  produced  by  burning  sul- 
phury coals  in  a  drying-stove.  We  have  seen  a  whole  stove- 
charge  of  goods,  yarn,  and  cloth,  spoiled  in  this  way ;  the 
colors  appearing  as  if  dried  in  smoke,  and  the  watchman  super- 
intending the  stove,  notwithstanding  his  protestations  that 
there  was  no  smoke,  compelled  to  bear  the  blame  of  negligence. 

Sulphur  combines  with  hydrogen  in  another  proportion,  and 
forms  a  bisulphuret  HS2,  which  is  an  oily  liquid  of  no  known 
importance  in  any  process  of  the  dye-house. 


Fig.  10. 


SELENIUM — PHOSPHORUS. 


103 


Selenium  (Se  39.5). 

This  element  very  much  resembles  sulphur  in  its  properties, 
and  in  some  of  its  combinations.  It  is  solid,  of  a  dark-brown 
color  and  metallic  lustre;  and  is  found  in  nature  in  combina- 
tion with  some  of  the  metallic  sulphurets,  as  those  of  copper, 
silver,  lead,  &c.  It  is  very  rare,  and  as  it  has  only  been  obtained 
in  minute  quantities,  it  has  not  yet  been  introduced  into  the 
arts,  or  applied  to  any  useful  purpose. 

Phosphorus  (P  32). 

Phosphorus  is  a  soft,  solid  substance,  of  a  light  amber  color, 
and  insoluble  in  water.  It  is  very  abundant  in  nature  in  com- 
bination with  other  substances,  but  principally  with  lime  in  the 
bones  of  animals.  It  is  exceedingly  inflammable,  oxidates 
rapidly  when  exposed  to  the  air,  and  emits  light  visible  in  the 
dark,  from  which  circumstances  it  derives  its  name.  It  is 
manufactured  from  the  bones  of  animals,  by  various  compli- 
cated methods  not  very  easily  imitated  on  a  small  scale. 

This  element  unites  with  oxygen  in  various  proportions,  and 
most  of  the  compounds  formed  have  acid  properties,  as : — 

Suboxide  of  phosphorus   P20. 

Hypophosphorous  acid   PO. 

Phosphorous  acid   P03. 

Phosphoric  acid   P05. 

These  acids  all  unite  with  bases,  forming  salts  which  are 
interesting  in  their  relations  to  each  other,  and  also  to  salts  of 
other  acids.  Phosphoric  acid  and  the  phosphates  evince 
peculiar  properties  in  combining  with  various  proportions  of 
water,  and  producing  compounds  which  differ  characteristically 
from  one  another.  These  combinations  have  been  extensively 
investigated  by  Professor  Graham  and  other  chemists.  We 
are  not  aware  that  any  of  these  salts  are  used  in  the  operations 
of  dyeing,  except  in  so  far  as  they  constitute  a  portion  of  the 
salts  in  dung,  and  the  substance  called  dung  substitute,  used  in 
dyeing  turkey  reds  and  other  madder  colors. 

Phosphorus  combines  also  with  hydrogen,  nitrogen,  chlorine, 
and  sulphur,  and  likewise  with  many  of  the  metallic  elements 
forming  the  class  of  compounds  termed  phosphurets,  or  phos- 
phides. 


IODINE. 


Iodine  (I  127). 

Iodine  is  obtained  from  the  ashes  of  sea-weed.  The  ashes 
are  put  into  water,  and  the  soluble  portions  are  withdrawn 
and  boiled  down.  During  the  process  common  salt  and  other 
salts  are  deposited  and  withdrawn  ;  and  when  the  liquid  is 
reduced  to  a  very  small  quantity  and  attains  a  dark  color,  a 
little  sulphuric  acid  is  added;  the  whole  is  then  allowed  to 
remain  at  rest  for  a  day  or  two.  The  liquor  is  then  mixed  up 
with  oxide  of  manganese,  and  put  into  a  retort,  to  which  heat 
is  applied.  The  iodine  distils  over,  and  is  condensed  in  re- 
ceivers fitted  to  the  retort. 

Iodine  is  a  solid  substance,  of  a  metallic  lustre,  and  a  bluish 
black  color ;  it  stains  the  hands  yellow  if  touched,  and  is 
volatile  at  a  low  heat,  rising  in  vapor  of  a  beautiful  violet 
color.  It  combines  with  nearly  all  the  non-metallic  elements, 
and  also  with  the  metals;  with  many  of  the  latter  it  forms 
compounds  having  beautiful  colors,  suitable  in  every  way  as 
dyes.  But  from  the  volatile  nature  of  iodine,  the  colors  pro- 
duced by  it  are  fugitive,  and  do  not  bear  exposure.  Many 
attempts  have  been  made  to  employ  the  salts  of  iodine  as  dye- 
drugs,  and  to  fix  the  color,  but  they  have  all  failed. 

The  compounds  of  iodine  with  oxygen  are  the  two  acids  : — 

Iodic  acid    .    .    I05        |        Hyperiodic  acid  .    .  I07. 

These  acids  combine  with  bases  to  form  salts  termed  iodates. 
It  forms  an  acid  with  hydrogen,  namely  : — 

Hydriodic  acid  ....  HI. 

The  salts  which  this  acid  forms  are  termed  hydriodates. 

Iodine  combines  with  starch,  and  forms  a  deep  blue  violet 
color,  which  soon  passes  away.  The  principal  compound  with 
which  experiments  upon  the  colors  formed  by  iodine  may  be 
carried  on,  is  the  iodide  of  potassium,  KI.  This  is  easily  pre- 
pared by  boiling  iodine  in  a  solution  of  caustic  potash  to  dry- 
ness, then  fusing  the  dry  mass  in  an  iron  vessel  or  crucible. 
The  result  of  this  is  iodide  of  potassium,  which  is  easily  soluble 
in  water.  This  salt  is  abundant,  and  always  very  pure  in  com- 
merce. A  little  of  the  solution  added  to  a  salt  of  lead  produces 
a  beautiful  yellow  precipitate,  which,  when  boiled  Jin  water, 
and  the  clear  part  set  aside  to  cool,  gives  brilliant  golden- 
colored  crystals  in  scales.  The  salts  of  mercury  give  with 
iodide  of  potassium  a  deep  orange-red  precipitate.  This  salt 
indeed  gives  precipitates  and  colors  with  the  salts  of  nearly  all 
the  metals ;  and,  were  it  possible  to  render  the  colors  it  affords 


BROMINE — FLUORINE. 


105 


permanent,  it  would  no  doubt  become  a  most  useful  drug  in 
the  hands  of  the  operative  dyer. 

Bromine  (Br  80). 

Bromine  is  another  element  obtained  from  the  ashes  of 
certain  sea-weeds,  but  not  in  nearly  so  great  abundance  as 
iodine.  It  is  a  liquid  at  ordinary  temperatures ;  has  a  deep 
red  color,  and  is  much  heavier  than  water,  in  which  it  is 
generally  kept  to  prevent  it  volatilizing,  as  it  does  rapidly  when 
exposed  to  the  air.  It  has  a  very  penetrating  odor,  and  its 
fumes  destroy  vegetable  coloring  matters,  leaving  merely  a 
yellow  tint. 

Bromine  is  known  to  combine  with  oxygen  in  only  one 
proportion  =  Br05.  This  is  bromic  acid,  which  combines 
with  bases,  forming  the  salts  termed  bromates.  With  hydro- 
gen it  combines  and  forms  hydrobromic  acid  =  HBr,  the  salts 
of  which  are  termed  hydrobromates.  It  also  unites  directly 
with  some  of  the  other  elements  forming  bromides,  of  which 
the  bromide  of  potassium  is  an  example.  The  compounds  of 
bromine  with  some  of  the  metals  might  also  form  a  dye,  were 
they  procured  abundantly ;  but  the  same  objection  to  iodine 
is  also  applicable  to  bromine,  it  is  unstable,  and  vanishes  on 
exposure. 

Bromine  and  some  of  its  compounds  have  been  much  used 
in  the  operations  of  daguerreotyping. 

Fluorine  (M  19). 

This  element  is  only  known  in  combination,  and  has  never 
been  obtained  free.  By  its  powerful  attraction  for  every 
other  substance,  it  fulfils  in  some  degree  the  old  hypothetical 
notion  of  a  universal  solvent.  It  is  however  very  abundant 
in  nature,  combined  with  calcium  as  a  fluoride,  forming  the 
mineral  fluor  spar.  It  is  not  known  to  combine  with  oxygen, 
but  it  combines  very  readily  with  hydrogen,  and  forms  hydro- 
fluoric acid  =  HF1.  This  acid  may  be  evolved  from  fluor 
spar  by  acting  upon  it  with  sulphuric  acid.  It  dissolves  glass, 
and  all  matters  containing  silica,  and  therefore  cannot  be  kept 
in  glass,  china,  or  earthenware  vessels;  and  as  it  dissolves  all 
metals  except  lead,  silver,  gold,  and  platinum,  it  can  only  be 
kept  in  vessels  made  of  any  of  these  metals,  but  lead  bottles 
are  commonly  used.  By  mixing  fluorspar  and  pieces  of  glass 
or  fine  sand,  and  acting  upon  the  mixture  by  strong  sulphuric 
acid,  an  acid  gas  is  given  off;  this  is  fluosilicic  acid  =  SiFl3, 


106 


SILICI  IT M — BORON — CARBON. 


which,  together  with  hydrofluoric  acid,  combines  with  water, 
and  is  termed  hydrofluosilicic  acid  =  3HF1 +  2SiFl3.  This 
solution  is  occasionally  used  in  the  laboratory  as  a  test  for 
potash  and  soda. 

« 

Silicium  (Si  21.3). 

Silicium  is  a  light-brown  powder.  It  is  one  of  the  most 
extensively  diffused  elements  in  nature,  but  it  always  exists  in 
combination  with  oxygen,  forming  silica  or  silicic  acid  =  Si  03. 
The  substances  known  as  flints,  agates,  quartz,  sand,  &c,  are 
nearly  pure  silica,  and  every  other  earthy  substance  in  nature 
contains  more  or  less  silica  combined  with  it.  This  substance 
is  of  essential  importance  to  the  potter  and  glass-maker,  but 
it  is  of  little  consideration  in  dyeing. 

Boron  (B  11). 

Boron  is  a  solid,  and  generally  obtained  as  a  greenish  brown 
powder,  destitute  of  metallic  lustre.  It  is  not  found  in  nature 
except  in  combination  with  oxygen,  with  which  it  forms 
boracic  acid  =  B03.  This  acid  combines  with  bases  forming 
borates;  but  it  is  found  in  nature  uncombined,  especially 
among  the  volcanic  products  of  the  Lipari  Islands.*  The  prin- 
cipal sources  of  the  compounds  of  boron  are,  however,  some 
springs  in  India,  and  the  waters  of  Sasso,  which  hold  in  solu- 
tion a  quantity  of  borate  of  soda  (borax).  In  some  lakes  in 
the  neighborhood  of  volcanoes  there  are  also  great  quantities 
of  boracic  acid.  These  waters  are  concentrated  by  evaporation 
sufficiently  to  allow  the  acid  to  crystallize,  and  in  this  state  it 
is  known  in  commerce  as  raw  borax.  Arrived  in  this  country, 
it  is  dissolved  and  saturated  with  soda  to  form  borate  of  soda, 
which  is  obtained  in  large  crystals  ;  this  is  the  refined  borax 
of  commerce,  and  the  principal  compound  of  boron  known  in 
the  arts.  It  is  much  used  in  medicine,  and  as  a  flux  in  the 
operations  of  metallurgy. 

Carbon  (C  6). 

Carbon  is  very  extensively  diffused  through  nature,  and  the 
complete  description  of  this  element  and  its  compounds  would 
embrace  the  whole  chemistry  of  organic  matter.    It  is  met 

*  The  greater  part  of  boric  acid  is  actually  extracted  from  the  suffioni  of 
Tuscany. 


CARBON. 


107 


with  also  in  various  forms  and  combinations  in  the  mineral 
kingdom.  Carbon  exists  pure  in  diamond  and  coal,  and  forms 
nearly  the  whole  of  plumbago  and  graphite  (popularly  Hack- 
lead)-  It  may  be  obtained  by  submitting  either  animal  or 
vegetable  matter  to  a  high  heat  in  a  close  vessel  ;  the  oxygen, 
hydrogen,  and  nitrogen  of  these  bodies  pass  off,  and  the  car- 
bon is  left.  Charcoal  is  therefore  carbon  with  a  little  earthy 
matter ;  and  coke,  ivory-black  and  lampblack,  are  other 
familiar  names  for  it  in  an  impure  state.  These  substances 
differ  in  character  from  each  other  in  having  different  propor- 
tions of  earthy  ingredients  in  combination  or  mixture  with  the 
principal  element.  Carbon  is  infusible,  therefore  we  only  know 
it  in  a  solid  form.  It  possesses  many  singular  properties  con- 
nected with  the  principles  of  dyeing  ;  some  of  these  we  will 
state  here  and  reserve  the  applications  till  we  come  to  consider 
the  methods  and  theory  of  dyeing. 

Carbon  has  the  property  of  absorbing  gases  within  its  pores. 
One  cubic  inch  of  the  best  charcoal  made  from  box-wood  has 
been  found  to  absorb  or  imbibe  the  following  quantities  of  the 
different  gases  named  : — 

Cubic  inches. 

90  Ammoniacal  gas. 

85  Hydrochloric  acid  gas. 

65  Sulphurous  acid. 

55  Sulphureted  hydrogen. 

40  Peroxide  of  nitrogen. 

35  Carbonic  acid. 

9  Oxygen. 

7  Nitrogen. 
1.7  Hydrogen. 

This  curious  property  is  not  well  understood  ;  it  is  generally 
supposed  that  it  results  from  the  powerful  cohesive  attraction 
between  the  gas  and  the  surface  of  the  charcoal  by  which  the 
gas  is  liquefied.  Somewhat  analogous  to  this  property  is  its 
power  of  absorbing  or  imbibing  coloring  matters,  and  on  this 
account  it  is  extensively  used  for  discoloring  sugar  ;  charcoal 
has  also  the  property  of  keeping  water  sweet  for  a  long  time. 
The  various  kinds  of  charcoal  possess  this  discoloring  power 
differently,  probably  depending  on  their  state  of  purity. 
Supposing  that  the  substance  to  be  discolored  is  sulphate  of 
indigo,  the  following  are  the  powers  of  some  kinds  of  charcoal 
compared  with  that  of  charcoal  from  bones,  which  we  call  1 : — 


108 


CARBONIC  ACID. 


Lampblack  =  4 

Charcoal  from  starch,  ignited  with  potash  .  .  =  12 
Lampblack,  ignited  with  carbonate  of  potash  =16 
Ivory-black,  ignited  with  carbonate  of  potash  =  45 
Blood  charcoal,  ignited  with  carbonate  of  potash  =50 

This  property  of  absorbing  colors  is  also  considered  an 
attraction  of  surface,  and  it  is  found  in  some  cases  to  be  suffi- 
ciently strong  to  overcome  chemical  affinity.  The  same  pro- 
perty of  imbibing  colors  is  possessed  by  other  porous  matters 
to  some  extent,  and  the  porous  nature  of  the  fibre  of  cotton, 
woollen,  and  silk,  may  exercise  an  influence  of  a  similar  kind, 
a  subject  which  we  intend  to  consider  farther  on. 

Carbon  combines  with  oxygen  in  three  proportions,  form- 
ing :— 

Carbonic  oxide,  or  oxide  of  carbon    .    .    .  CO. 

Carbonic  acid  C02. 

Oxalic  acid  C2,  03. 

Carbonic  Oxide  is  obtained  by  heating  together  strong  vit- 
riol and  crystallized  oxalic  acid.  This  operation  may  be  per- 
formed in  a  retort  or  flask,  as  described  for  hydrogen  (page  50) ; 
the  action  taking  place  is : — 

'Carbon   -p-Oxide  of  carbon. 

Vvarbon ^^Z^  Carbonic  acid. 


Crystallized    ,  Oxygen , 
oxalic  acid,  }  Oxygen 
"  Oxygen 
Water. 


phurkfacii  }  SulPhuric  acid  Sulphuric  acid. 

The  action  is  simply  the  sulphuric  acid  taking  the  water 
from  the  crystallized  oxalic  acid  and  setting  the  elements  free. 
By  passing  the  gases  through  a  solution  of  caustic  potash  or 
lime-water,  the  carbonic  acid  is  absorbed,  and  carbonic  oxide 
is  obtained  pure.  It  is  a  colorless  gas,  inodorous,  and  burns 
with  a  blue  flame.  It  is  the  presence  of  this  gas  which  gives 
the  blue  flame  of  a  coke  fire.  The  product  of  its  combustion 
is  carbonic  acid. 

Carbonic  Acid. — When  carbon  is  brought  to  a  red  heat,  it 
burns  and  dissipates;  the  oxygen  combines  with  the  carbon, 
and  produces  gaseous  carbonic  acid.  This  gas  is  generally 
obtained  for  experiment  from  its  compounds.  Thus,  when  a 
few  pieces  of  marble  or  chalk  are  put  into  a  flask  or  retort,  and 
some  dilute  muriatic  acid  is  added,  effervescence  takes  place, 
and  the  action  is  : — 


OXALIC  ACID. 


109 


Marble.... 


<  Calcium  . 
(Oxygen.  . 
J  Hydrogen 
(Chlorine . 


(  Carbonic  acid 


Carbonic  acid. 


Muriatic 
acid 


Water. 

Chloride  calcium. 


Carbonic  acid  is  absorbed  by  water,  in  quantity  equal  to  the 
volume  of  the  gas ;  but  the  materials  from  which  it  is  prepared 
are  so  cheap,  that  this  absorption  does  not  signify  much  in  an 
experiment.  The  gas  is  colorless,  and  heavier  than  atmospheric 
air,  so  that  it  may  be  poured  from  one  vessel  to  another,  as  if 
it  were  a  liquid.  A  light  is  instantly  extinguished  by  immer- 
sion "in  an  atmosphere  of  it,  and  an  animal  soon  dies  if  kept  in 
air  containing  nine  per  cent,  of  it.  Combined  with  water,  it 
manifests  acid  properties,  and  gives  the  water  an  agreeable 
taste  and  pungency,  as  experienced  in  aerated  waters.  It  com- 
bines readily  with  alkaline  and  earthy  bases,  producing  car- 
bonates. Its  affinity  for  lime  is  very  great;  but  it  is  liberated 
from  all  its  compounds  with  effervescence  by  a  stronger  acid. 
When  the  dry  gas  is  passed  over  redhot  charcoal,  it  is  decom- 
posed ;  the  charcoal  combines  with  half  its  oxygen,  and  forms 
oxide  of  carbon. 

Oxalic  Acid  has  been  long  known  in  commerce  as  salt  of 
sorrel.  It  was  formerly  obtained  from  the  oealis  acetesella,  a 
plant  which  contains  it  as  oxalate  of  lime  ;  but  it  is  now  manu- 
factured in  large  quantities  from  sugar  and  starch,  by  acting 
upon  these  substances  with  nitric  acid,  which  oxidates  and  de- 
composes them.    The  action  is  probably  as  follows : — 

6  proportions  of  f  6  Binoxide  of  nitrogen  given  off. 


The  acid  crystallizes  with  water,  which,  as  has  been  shown 
above,  is  essential  to  its  existence.  It  combines  with  bases, 
and  forms  salts  of  great  importance  in  the  laboratory.  Thus 
the  oxalates  of  potash  and  ammonia  are  excellent  tests  for  lime; 
and  they  are  also  of  some  importance  in  the  dye  house,  as  are 
also  the  oxalates  of  tin,  &c.  Oxalic  acid  is  easily  distinguished 
from  any  of  the  alkaline  and  earthy  salts,  such  as  the  sulphate 
of  magnesia  (Epsom  salts),  for  which  it  has  occasionally, 
through  ignorance,  been  mistaken  by  its  strong  acid  character. 
It  is  easily  detected  by  heating  it  to  redness  upon  a  piece  of 
platinum,  when  it  will  all  evaporate,  and  leave  no  residue, 
while  the  magnesian  salt  does.  It  sometimes  contains  nitric 
acid,  peroxide  of  nitrogen,  and  Epsom  salts  ;  the  first  two  may 


Sugar, 
composed  of 


nitric  acid 


110 


CYANOGEN. 


be  detected  by  dissolving  a  little  of  the  acid,  and  adding  a 
minute  coloring  of  sulphate  of  indigo,  and  then  boiling;  the 
presence  of  these  impurities  decolors  the  indigo.  The  presence 
of  Epsom  salts  may  be  detected  by  chloride  of  barium,  or  by 
evaporation  as  directed  above.  There  is  often  about  one  per 
cent,  of  this  salt  in  the  commercial  oxalic  acid. 

This  acid  has  been  long  used  in  the  dye-house,  and  acts  pow- 
erfully upon  many  substances,  but  it  is  not  now  so  generally 
used.  A  curious  salt,  of  a  beautiful  color,  may  be  obtained  by 
taking 

One  part  of  bichromate  of  potash, 
Two  of  binoxalate  of  potash, 
Two  of  oxalic  acid ; 

and  dissolving  the  whole  together  in  hot  water,  when  carbonic 
acid  is  evolved,  and  a  double  salt  of  oxalate  of  potash  and 
chrome,  having  a  fine  purple  color,  is  formed  in  solution. 
Crystals  of  the  salt,  possessing  a  very  deep  blue  color,  may  be 
obtained  by  evaporation. 

Cyanogen — Carbon  combines  with  nitrogen,  and  forms 
cyanogen,  a  very  important  compound,  consisting  of  one  equi- 
valent of  nitrogen  and  two  equivalents  of  carbon  =  C2N.  It 
is  a  gas,  and  has  the  property  of  combining  with  other  ele- 
ments as  if  it  were  itself  an  element.  It  belongs  therefore,  as 
was  stated  at  p.  45,  to  the  class  of  compounds  known  as  salt 
radicals.  It  is  not  obtained  by  directly  bringing  nitrogen  into 
contact  with  carbon,  but  by  the  decomposition  of  animal  com- 
pounds in  contact  with  metallic  bases,  as  we  will  have  occasion 
to  describe  farther  on.  The  gas  is  generally  obtained  for  ex- 
periment from  its  salts,  by  heating  cyanide  of  mercury  in  a 
retort.  The  mercury  runs  over  in  a  metallic  state,  and  the 
cyanogen  escapes  as  gas,  and  may  be  caught  at  the  pneumatic 
trough.  Cyanogen  combines  with  oxygen,  and  forms  an  acid 
called  cyanic  acid,  and  this,  combining  with  bases,  forms 
cyanates. 

Cyanogen  combines  also  with  hydrogen,  and  forms  an  acid 
termed  hydrocyanic  acid,  or  more  commonly  prussic  acid, 
which,  like  hydrochloric  acid,  does  not  combine  with  bases,  as 
C2N-f  H,  and  although  certain  salts  are  termed  prussiates,  they 
are  properly  cyanides.  Some  of  them  are  highly  important  in 
the  arts,  and  will  be  noticed  in  their  proper  places. 

Cyanogen  also  combines  with  the  metals  in  the  same  man- 
ner as  chlorine  and  iodine,  and  forms  that  class  of  salts  termed 
cyanides* 

*  The  distinction  between  the  names  ending  in  ate  and  ide  must  here  be 
borne  in  mind. 


MELLON. 


Mellon. — Carbon  combines  with  nitrogen  in  other  propor- 
tions besides  that  of  cyanogen.  There  is  one  expressed  by 
N4C6,  which  is  a  solid  substance  of  a  lemon-yellow  color,  in- 
soluble in  water,  but  which  acts  the  part  of  a  salt  radical,  and 
combines  with  hydrogen  to  form  an  acid  which  also  combines 
with  several  of  the  metallic  bases.  This  salt  radical  is  termed 
Mellon,  and  the  salts  from  it  are  termed  mellonides ;  but 
these  compounds  are  not  so  well  known  as  the  cyanides,  and 
they  are  less  useful. 

Carbon  combines  with  hydrogen  in  various  proportions, 
forming  different  kinds  of  gases,  such  as  light  carbureted  hy- 
drogen =  CH2;  olefiant  gas  =  C4H4;  common  coal  gas,  and 
some  other  hydrocarbons  consist  of  those  gases  as  constitu- 
ents. Carbon  also  combines  with  sulphur,  and  forms  with  it  a 
colorless,  volatile,  and  inflammable  liquid,  possessing  a  most 
putrid  smell :  this  is  sulphuret  of  carbon.  In  organic  bodies, 
carbon  is  combined  with  oxygen,  hydrogen,  and  nitrogen,  in 
an  endless  variety  of  proportions.  Some  of  these  compounds 
will  be  brought  under  notice  when  treating  of  the  organic  sub- 
stances which  fall  within  the  scope  of  our  subject. 


112 


METALLIC  SUBSTANCES. 

General  Properties  of  Metals. 

We  now  proceed  to  consider  that  division  of  the  elements 
commonly  known  as  metals.  To  define  the  peculiar  properties 
of  a  metal  is  somewhat  difficult,  for  whichever  property  we 
select,  it  is  either  absent  in  some  metal,  or  it  is  possessed  by 
some  non-metallic  element.  A  few  of  the  more  prominent 
physical  properties  may,  however,  be  named. 

1st.  They  all  possess  a  peculiar  lustre.  2d.  They  all  reflect 
light,  which  is  the  cause  of  that  lustre.  3d.  They  are  all 
fusible  by  heat,  and  while  in  fusion  retain  their  lustre.  4th. 
They  are  all  conductors  of  light  and  heat.  5th.  They  have 
all  to  a  certain  degree  the  property  of  extension  ;  they  are 
malleable  under  the  hammer;  and  laminahle  under  the  roller; 
and  being  capable  of  extension  by  drawing  into  wire,  they  are 
termed  ductile. 

There  are  also  chemical  distinctions  which  are  much  more 
universal.  They  are  all  basic,  that  is  to  say,  capable  of  com- 
bining with  oxygen,  and  forming  oxides;  and  with  acids  they 
form  a  series  of  compounds  termed  salts,  of  which  the  metal 
is  termed  the  base.  It  is  on  account  of  the  possession  of  these 
general  properties  that  hydrogen  is  regarded  as  a  metal  in  a 
gaseous  state  ;  it  is  pre  eminently  basic. 

When  metals  combine  with  one  another,  the  compound  is 
termed  an  alloy.  Brass  is  a  chemical  mixture  of  copper  and 
zinc;  and  German  silver  is  a  like  mixture  of  copper,  zinc,  and 
nickel ;  both  brass  and  German  silver  are  therefore  alloys. 
Alloys  retain  most  of  the  physical  properties  of  the  metals  of 
which  they  consist.  A  great  many  of  the  recently  discovered 
metals  are  very  rare,  and  have  only  been  found  in  certain 
localities,  and  in  minute  quantities.  The  alkalies  and  earths 
were  long  looked  upon  as  elements ;  they  had  never,  indeed, 
been  decomposed  till  1807.  What  was  until  that  time  known 
as  the  element — 

Potash,  we  now  know  to  be  the  oxide  of  the  metal  Potassium. 

Soda  Sodium. 

Lithia   Lithium. 

Lime  Calcium. 

Barytes  or  Baryta  Barium. 

Magnesia  Magnesium. 

Alumina  Aluminum. 


POTASH. 


113 


Potassium  (K  39.2). 

Sir  H.  Davy  decomposed  potash  by  a  powerful  electric 
current,  and  demonstrated  it  to  be  the  oxide  of  a  peculiar 
metal  which  he  termed  potassium.  This  metal  may  be  ob- 
tained easily  by  roasting  a  quantity  of  bitartrate  of  potash 
(cream  of  tartar)  in  a  covered  crucible :  the  immediate  product 
is  what  is  termed  black  flux  ;  then  mixing  this  matter  with  a 
quantity  of  finely-ground  charcoal,  and  putting  the  whole  into 
a  wrought-iron  bottle,  and  distilling  it  at  a  high  heat,  the  metal 
comes  over,  and  is  caught  in  a  vessel  containing  naphtha,  a 
fluid  that  contains  no  oxygen.  Only  such  a  fluid  can  be  used 
for  this  purpose,  as  the  attraction  of  potassium  for  oxygen  is 
so  great,  that  it  decomposes  all  substances  which  contain  that 
element. 

Potassium  is  a  white  metal,  with  a  lustre  somewhat  like 
silver;  at  ordinary  temperature  it  is  soft,  and  may  be  flattened 
between  the  fingers,  but  at  32°  it  is  hard  and  brittle.  It  melts 
at  136°.  When  exposed  to  the  air,  it  becomes  covered  imme- 
diately with  a  white  crust  of  oxide.  It  is  lighter  than  water, 
and  when  thrown  upon  that  fluid  it  swims,  and  instantly 
bursts  into  flame,  combining  with  the  oxygen  of  the  water  so 
rapidly  as  to  produce  heat  sufficient  to  kindle  the  hydrogen  as 
it  makes  its  escape.  The  metal  not  only  fuses,  but  a  small 
portion  of  it  goes  off  as  vapor,  and  burning  with  the  hydrogen 
produces  a  beautiful  red  colored  flame.  In  this  experiment 
potash  is  formed  in  the  water.  Pure  potash  is  the  oxide  of 
the  metal  potassium,  but  it  is  not  prepared  from  the  metal  for 
manufacturing  purposes. 

Potash. — Sometimes  termed  the  vegetable  alkali,  takes  its 
name  from  being  prepared  for  commercial  purposes  in  iron 
pots.  When  a  piece  of  wood,  or  other  vegetable  substance,  is 
slowly  burned  until  all  inflammable  matters  are  consumed, 
there  is  left  a  white  substance  called  ash.  This  ash  consists 
of  the  mineral  ingredients  of  the  vegetables,  along  with  potash, 
lime,  and  other  earthy  ingredients.  The  potash  and  other 
soluble  ingredients  are  extracted  by  treating  the  ash  with 
water. 

The  average  quantity  of  ash  pbtained  from  wood  is  about 
one  per  cent.  In  America,  where  wood  is  an  incumbrance,  it 
is  felled,  piled  up  in  masses,  and  burned  for  the  manufacture 
of  potash.  The  ashes  of  the  wood  are  collected  and  put  into 
cisterns  provided  with  false  bottoms,  and  run-off  plugs  under- 
neath. A  quantity  of  water  is  thrown  upon  the  ashes  in  a 
cistern,  and  after  stirring  and  settling  a  few  hours,  all  the 
8 


114 


POTASH. 


soluble  matters  are  dissolved,  and  the  liquor  is  drawn  off, 
evaporated  to  dryness,  and  the  residue  afterwards  fused  at  a 
red  heat  into  compact  masses,  and  in  this  state  constitutes  the 
commercial  black  ash.  As  other  matters  besides  the  potash 
are  soluble  in  water,  the  black  ash  thus  prepared  contains 
these  substances  as  impurities.  These  are  mainly  sulphites, 
sulphurets,  and  chlorides  of  potash,  along  with  some  earthy 
matters. 

Pearlash  is  prepared  by  calcining  the  black  ash  in  a  rever- 
beratory  furnace  until  all  the  carbonaceous  matters  and  the 
sulphur  are  driven  off.  The  remaining  mass  is  then  dissolved 
in  water,  and  the  solution  evaporated  to  dryness  in  large  iron 
pans.  Towards  the  conclusion  of  the  process,  the  mass  is 
stirred  to  give  it  a  lumpy  granulation.  This  ash  contains 
much  less  extraneous  matter  than  black  ash,  and  is  conse- 
quently weaker  as  an  alkali.  It  is  more  fully  carbonated. 
Dr.  Ure  states  [Dictionary  of  Arts,  &c.)  that  he  found  the 
best  pink-colored  Canadian  potash  to  contain  60  per  cent,  of 
real  potash,  while  the  best  pearlash  contained  only  50  per 
cent.  These  are  the  two  states  in  which  potash  is  introduced 
into  the  dye-house.  The  methods'for  testing  the  quantity  of 
real  alkali  they  contain  will  be  given  when  we  come  to  speak 
of  soda. 

The  principal  use  of  potash  is  to  destroy  or  take  off  any 
grease  or  oil  which  may  exist  in  or  upon  the  fibre  to  be  dyed, 
and  it  does  this  by  combining  with  these  substances  and  form- 
ing soap  which,  being  soluble  in  water,  is  easily  removed. 
Dyers  are  often  in  the  habit,  when  about  to  steep  or  boil  their 
goods,  of  simply  adding  to  their  solution  or  boiler,  some  pearl- 
ash or  potash,  but  as  the  alkali  is  in  union  with  an  acid  (car- 
bonic acid)  forming  a  carbonate,  its  power  of  combining  with 
oil  or  grease  is  to  a  great  extent  neutralized.  The  white  ob- 
tained upon  the  fabric  may  be  good  enough,  and  as  was  before 
remarked  when  speaking  of  chlorine,  a  good  white  can  be  got 
without  potash  ;  but  it  is  not  so  permanent.  If  grease  or  oil 
be  present  it  is  not  removed,  but  only  concealed,  and  the 
dyer  is  often  annoyed  by  large  resist  spots  which  he  cannot 
account  for,  and  which  are  not  so  easily  removed  after  the 
goods  are  boiled  as  before.  The  alkali,  whether  pearl  or 
potash,  before  being  used  ought  to  be  made  caustic,  that  is, 
deprived  of  its  carbonic  acid,  and  converted  into  oxide  of 
potassium.  This  is  done  by  boiling  the  carbonated  alkali  with 
newly  slaked  lime  ;  the  lime  combines  with  the  carbonic  acid 
of  the  alkali,  and  falls  to  the  bottom,  while  the  caustic  alkali 
remains  in  solution.  Without  detailing  the  various  methods 
practised,  some  of  which  are  not  good,  we  shall  rather  give 


POTASH. 


115 


what  we  consider  the  best.  The  carbonate  of  potash  ought  to 
be  dissolved  in  not  less  water  than  six  times  its  weight;  it  is 
better,  however,  to  use  ten  times  its  weight,  as  if  a  less  quan- 
tity of  water  be  used,  the  potash  is  not  deprived  of  all  its  car- 
bonic acid.  The  reason  assigned  for  this  singular  phenomenon 
is,  that  both  caustic  potash  and  its  carbonate  have  a  strong 
affinity  for  water,  and  when  less  than  six  times  its  weight  is 
used,  there  is  sufficient  water  to  supply  the  carbonate,  but  not 
the  caustic  alkali,  and  hence  the  carbonate  is  not  converted 
into  the  caustic  state.  The  exact  quantity  of  lime  is  not  ma- 
terial, provided  there  be  enough.  The  lime  ought  to  be  added 
when  the  alkali  is  boiling,  and  from  time  to  time,  until,  a  little 
of  the  solution  being  taken  out,  it  does  not  effervesce  by  the 
addition  of  a  little  dilute  sulphuric  acid.  If  strong  acid  is 
used,  care  must  be  taken  before  adding  it  that  the  solution  be 
cold,  for  if  not,  it  will  spirt,  and  may  injure  the  manipulator. 
The  best  way  is  to  take  a  little  of  the  alkali  and  dilute  it  with 
cold  water,  and  then  add  the  acid.  When  there  is  no  effer- 
vescence, the  alkali  is  caustic.  The  boiling  is  then  stopped, 
and  when  the  lime  settles  the  clear  is  taken  off  and  kept  in  an 
iron  vessel  covered  closely,  as  the  potash  readily  takes  up  car- 
bonic acid  from  the  air.  For  bleaching,  and  other  cleansing 
operations,  and  also  for  many  purposes  in  the  dye-house,  the 
supply  should  be  taken  from  this  stock  vessel.  It  will  be 
necessary,  however,  that  the  operator  know  the  exact  strength 
of  the  solution,  in  order  that  he  may  know  the  proper  quanti- 
ties of  it  he  ought  to  use  for  particular  purposes.  On  this 
point  a  pretty  correct  approximation  is  obtained  by  knowing 
the  percentage  of  pearl  or  potash  used  in  making  the  solution, 
and  then  calculating  the  quantity  to  each  gallon  ;  but  greater 
exactness  is  attained  by  using  the  following  table  (drawn  up 
by  Dr.  Dalton),  in  which  the  specific  gravity  is  supposed  to  be 
known,  and  hence  the  quantity  present  of  the  alkali  in  solu- 
tion : — 


116 


POTASH. 


Potash  per  cent,  in 
solution. 

Specific  gravity  of 
solution. 

Specific  gravity  by 
xwaaaen  s. 

Boiling  point  of 
solution. 

'  72.4 

2.000 

200° 

600° 

63.6 

1.880 

176 

420 

56.8 

1.780 

156 

360 

51.2 

1680 

136 

320 

46.7 

1.600 

120 

290 

42.9 

1.520 

105 

276 

39.6 

1-470 

94 

265 

36.8 

1.440 

88 

255 

34.4 

1.420 

84 

246 

32.4 

1.390 

78 

240 

29.4 

1.360 

72 

234 

26.3 

1.330 

66 

229 

23.4 

1.280 

56 

224 

19.5 

1.230 

46 

220 

16.2 

1.190 

38 

218 

13. 

1.150 

30 

215 

9.5 

1.110 

20 

214 

4.7 

1.060 

12 

213 

/ 


In  the  first  column  of  this  table  the  percentage  of  alkali  is 
given  by  weight.  Thus  a  gallon  of  water  is  10  lbs.  weight, 
therefore  a  gallon  of  the  caustic  lye  solution  will  have  one- 
tenth  part  of  the  potash  indicated  by  the  table  according  to 
the  specific  gravity.  Say  the  solution  stands  30°  by  Twad- 
dell — the  percentage  of  this  is  13,  and  this  divided  by  10 
gives  1.3  lb.  =  1  lb.  5  oz.  nearly  of  caustic  potash  to  a  gallon 
of  the  lye.  The  stock  lye  should  not  be  made  stronger  than  this. 

In  the  last  column  the  boiling  points  of  the  solution  at  dif- 
ferent strengths  are  entered.  These  numbers  are  important, 
and  explain  to  some  extent  why  boiling  by  steam  is  not  so 
effective  as  by  fire ;  for  the  steam  heat  as  was  stated  at  page 
22,  is  not  higher  than  210°,  whereas  the  lowest  temperature 
noted  in  the  table  is  213°. 

Potash,  as  used  in  the  dye-house,  is  never  chemically  pure. 
Even  when  used  as  caustic,  it  generally  contains  lime  and  soda, 
and  often  their  sulphurets.  Lime  may  be  detected  by  adding 
a  little  clear  solution  of  carbonate  of  potash  to  a  clear  solution 
of  the  caustic  potash,  when  its  presence  will  be  known  by  the 
milkiness  produced.  It  is  not,  however,  detrimental  to  the  dyer 
in  the  operations  in  which  potash  is  commonly  used.  Sulphu- 
rets may  be  detected  by  adding  to  a  dilute  solution  of  the 


SALTS  OF  POTASH. 


117 


potash  some  acetate  of  lead ;  if  a  sulphuret  is  present,  there 
will  be  a  blackish  precipitate.  Sulphurets  are  destructive  to 
gold  ornaments  on  muslin  and  other  cloths,  for  the  metal  is 
rarely  pure ;  commonly  it  is  an  alloy  of  gold  with  copper,  &c, 
and  sometimes  the  inferior  metal  is  merely  gilt.  The  sulphuret 
acts  upon  all  the  inferior  metals  by  contact,  and  at  least  black- 
ens them.  Potash  containing  sulphurets  should  therefore  be 
avoided  for  goods  having  such  ornaments. 

Caustic  potash  is  evaporated  to  dryness,  fused  and  poured 
into  moulds  to  form  it  into  small  cylinders;  in  this  state  it  is 
sold  by  druggists  under  the  name  of  stick-potash. 

Potash  has  a  strong  affinity  for  water,  and  deliquesces  rapidly 
when  exposed  to  the  air;  this  property  is  also  possessed  by 
the  carbonates. 

The  following  table  gives  the  average  quantity  of  pure  alkali, 
&c,  in  the  different  sorts  of  commercial  potash: — 


Name  of  place  from 
which  it  is  procured. 

Real 
potash. 

Sulphate 

of 
potash. 

Muriate 

of 
potash. 

Carbonic 
acid  and 
water. 

Insoluble 
ingredi- 
ents. 

Total. 

Potash  of  Kussia, 

772 

65 

5 

254 

56 

1152 

—  America, 

857 

154 

20 

119 

2 

1152 

American  pearl, 

754 

80 

4 

308 

6 

1152 

Potash  of  Treves, 

720 

165 

44 

199 

24 

1152 

—  Dantzic, 

603 

152 

14 

304 

79 

1152 

—  Vosges, 

444  • 

148 

510 

304 

34 

1440 

Potassium  combines  with  chlorine,  and  forms  chloride  of 
potassium — more  commonly  termed  muriate  of  potash  ;  which 
may  be  prepared  by  adding  hydrochloric  acid  to  caustic  potash, 
or  its  carbonate.  It  combines  also  with  iodine,  and  forms 
iodide  of  potassium  (page  104):-  with  bron^ide  it  forms  bro- 
mide of  potassium  ;  and  with  sulphur  it  forms  the  sulphuret,  or 
sulphide  of  potassium.  We  have  already  noticed  most  of  these 
salts. 

Sulphate  of  Potash. — When  sulphuric  acid  is  added  to 
potash,  it  forms  a  salt  which  has  neither  acid  nor  alkaline  pro- 
perties, and  which  is  easily  crystalized.  This  neutral  salt  is 
produced  abundantly  in  the  manufacture  of  nitric  acid  from 
nitre.  It  is  not  deliquescent*,  and  requires  15  times  its  own 
weight  of  water  to  dissolve  it. 

Bisulphate  of  Potash. — This  salt  is  also  obtained  like  the 
sulphate  in  the  process  of  making  nitric  acid  from  nitre;  but 
it  may  be  prepared  by  adding  to  the  sulphate  half  its  weight  of 
sulphuric  acid,  and  bringing  the  mixture  up  to  a  red  heat  in  a 


118 


SALTS  OF  POTASH. 


porcelain  or  platinum  vessel.  This  salt  has  strong  acid  reac- 
tions, is  very  soluble  in  water,  melts  easily  with  heat,  and  is 
exceedingly  useful  for  dissolving  metals,  many  of  which  may 
be  dissolved  by  it  easily,  although  of  very  difficult  solution  in 
the  pure  acid. 

Sulphite  of  Potash  is  prepared  by  passing  a  current  of 
sulphurous  acid  gas  through  a  solution  of  carbonate  of  potash 
till  saturated.  It  crystallizes,  and  should  be  kept  close,  as  it 
rapidly  passes  to  the  state  of  sulphate  by  exposure  to  the  air. 

Nitrate  of  Potash  may  be  prepared  by  saturating  potash 
with  nitric  acid  ;  but  it  is  obtained  abundantly  in  native  beds 
(page  62).  It  is  prepared  artificially  in  Germany  and  France, 
by  forming  large  beds  of  animal  and  vegetable  refuse,  in  which 
decomposition  is  effected  by  putrefaction.  Potash  is  present 
in  the  organic  matters,  and  these  also  yield  nitrogen  and  oxygen 
to  form  nitric  acid;  and  by  combination  the  nitrate  of  potash 
is  formed.  The  chief  uses  of  nitrate  of  potash  are  in  the  man- 
ufacture of  gunpowder  and  nitric  acid. 

Chlorate  of  Potash  is  prepared  by  passing  chlorine  gas 
through  carbonate  of  potash.  When  the  solution  is  saturated, 
crystals  of  this  salt  are  formed  (page  70).  This  salt,  as  already 
stated,  is  advantageously  used  in  several  operations  in  the  dye- 
house,  in  which  oxidation  is  required ;  also  with  decoctions  of 
some  of  the  woods.  When  mixed  with  substances  containing 
carbon,  it  gives  them  great  combustibility.  Thus,  if  a  drop 
of  sulphuric  acid  is  added  to  a  mixture  of  chlorate  of  potash 
and  sugar,  combustion  instantly  commences,  and  the  mixture 
burns  with  great  rapidity. 

Phosphate  of  Potash. — This  salt  is  obtained  by  adding 
carbonate  of  potash  to  a  hot  solution  of  phosphoric  acid,  until 
the  solution  ceases  to  redden  blue  litmus  paper.  By  careful 
evaporation  the  salt  may  be  crystallized. 

If  the  carbonate  of  potash  be  added  to  the  phosphoric  acid 
while  cold,  in  sufficient  quantity  to  saturate  it,  the  solution,  by 
evaporation,  gives  crystals  of  a  salt  having  two  proportions  of 
acid — a  biphosphate  of  potash. 

Oxalate  of  Potash. — This  salt  is  obtained  by  saturating 
carbonate  of  potash  with  oxalic  acid,  and  crystallizing.  In  this 
state  it  contains  one  proportion  of  water. 

The  Binoxalate  is  obtained  from  wood-sorrel,  in  which  it 
exists  ready  formed.  It  is  obtained  by  reducing  the  expressed 
juice  of  the  sorrel  to  the  consistence  of  a  syrup,  and  setting  it 
aside  to  crystallize.  It  is  sold  as  salt  of  sorrel  and  essential  salt 
of  lemons.  The  taste  of  the  salt  is  acid;  it  is  employed  for  re- 
moving ink  stains  from  goods,  and  recently  formed  iron  moulds. 
Its  crystals  are  composed  of  2  acid,  1  potash,  and  2  water. 


FERROCYANIDE  OF  POTASSIUM. 


119 


Ferrocyanide  of  Potassium. — This  salt  is  known  as  yellow 
prussiate  of  potash.  We  have  already  referred  to  the  corn- 
pound  salt  radical  termed  cyanogen,  and  stated  that  it  com- 
bines with  other  bodies,  and  forms  salts  resembling  the  chlorides ; 
but  it  is  occasionally  found  that  two  such  salts  group  together 
and  form  a  distinct  compound.  Thus,  one  proportion  of  the 
protocyanide  of  iron  ==  Fe  Cy,  combines  with  two  proportions 
of  cyanide  of  potassium,  =2  Cy  K,  and  forms  the  ferrocyanide 
of  potassium.  These  two  proportions  of  potassium  may  be  re- 
placed by  another  metal,  but  the  iron  and  the  three  equivalents 
of  cyanogen  maintain  themselves  together.  It  has,  therefore, 
been  inferred  that  Fe  Cy3  is  a  distinct  salt  radical,  which  may 
be  termed  ferro-prussic  acid ;  a  theoretical  deduction  very  in- 
teresting to  study,  and  which  will  be  more  fully  developed  as 
we  proceed.  The  salts  formed  by  this  acid  are  distinguished 
by  the  prefix  ferro. 

The  ferrocyanide  of  potassium,  or  prussiate  of  potash,  is 
prepared  on  a  large  scale  by  calcining  together  dried  blood, 
hoofs,  horns,  hides,  old  woollen  rags,  or  similar  materials,  with 
carbonate  of  potash,  in  an  iron  vessel ;  commonly  those  sub- 
stances are  partly  carbonized  or  burnt  in  large  cast-iron  cylin- 
ders previously  to  being  mixed  with  the  potash.  If  the  animal 
matters  are  used  without  being  subjected  to  this  preliminary 
process,  they  are  mixed  in  the  ratio  of  about  8  to  1  of  pearlash  ; 
but  if  burned  previously,  one  and  a  half  of  the  charcoal  is 
mixed  with  one  of  pearlash.  When  the  animal  matters  are 
used  without  being  charred,  the  calcining  pot  is  left  open  to 
allow  the  materials  to  be  stirred  and  the  noxious  vapors  to  es- 
cape ;  after  which  the  vessel  is  closed,  and  the  heat  is  increased. 
This  is  continued  for  some  time,  and,  at  intervals  of  half  an 
hour,  the  mouth  of  the  vessel  is  uncovered  for  the  purpose  of 
stirring  the  matter  within.  This  process  is  continued  until  the 
flame  ceases  to  rise  from  the  surface  and  the  materials  are  re- 
duced to  a  red  semifluid  mass,  which  generally  takes  place  in 
about  eight  hours  after  the  pot  is  closed.  From  this  descrip- 
tion, the  nature  of  the  action  is  easily  understood.  The  animal 
matters  which  contain  nitrogen  and  carbon  abundantly  are 
decomposed  by  the  heat ;  but,  on  account  of  the  presence  of 
the  iron  and  potash,  definite  portions  of  the  elements  combine 
and  form  cyanogen,  which  is  simultaneously  taken  up  by  the 
potassium  and  iron,  and  we  have  two  proportions  of  cyanide 
of  potassium,  with  one  proportion  of  cyanide  of  iron.  The 
molten  mass  is  scooped  out  with  iron  ladles,  and  allowed  to 
cool.  When  the  mass  has  cooled,  it  is  dissolved  in  cold  water, 
and  the  solution  is  filtered  through  cloth.  Lest  any  cyanide 
of  potassium  should  remain  which  had  not  received  the  pro- 


120 


FERROCYANIDE  OF  POTASSIUM. 


portion  of  iron,  sulphate  of  iron  (copperas)  is  added  by  degrees 
to  the  solution,  so  long  as  the  Prussian  blue  which  is  at  first 
formed  on  adding  the  iron  salt  is  redissolved.  The  whole  is 
then  evaporated  to  a  proper  consistency ;  after  which,  pieces 
of  coarse  cord  are  suspended  throughout  the  liquid,  upon  which 
crystals  of  ferro-prussiate  are  formed  in  regular  bunches,  of  a 
beautiful  light  citron-yellow. 

Ferrocyanide  of  potassium  crystallizes  with  three  proportions 
of  water,  which  it  loses  at  212°.  It  dissolves  in  4  parts  of 
cold  and  2  parts  of  boiling  water.  From  this  salt  all  other 
ferrocyanides  are  derived  as  precipitates  ;  those  of  the  metals  are 
formed  by  adding  a  salt  of  the  metal  to  a  solution  of  the  prus- 
siate.  The  following  are  the  appearances  of  a  few  of  those 
precipitates,  corresponding  to  the  metals  employed: — 

Protoxide  of  Manganese   .  White,  turning  to  a  deep  red. 
Peroxide  of  Manganese    .  Greenish-gray. 
Oxide  of  Lead     ....  White,  with  a  yellowish  hue. 
Peroxide  of  Iron    .    .    .  Deep  blue. 

Protoxide  of  Iron  .  .  .  White,  turning  blue  by  exposure. 
Oxide  of  Copper  ....  Brown. 


Each  of  these  precipitates  is  a  ferrocyanide  of  the  metal 
used,  which  has  taken  the  place  of  the  potassium  ;  they  are  all 
insoluble  in  water,  and  where  a  color  can  be  obtained  by  them, 
they  are  suitable  for  a  dye,  although  the  colors  dyed  by  the 
yellow  prussiate  are  fugitive.  Every  alkaline  substance,  such 
as  soap,  destroys  them,  and  they  are  easily  affected  by  that 
universal  creator  and  destroyer  of  colors,  the  sun. 

The  principal  use  of  the  ferrocyanide  salt  in  the  dye-house 
is  for  dyeing  Prussian  blue.  To  dye  this  color,  the  goods  are 
impregnated  with  a  persalt  of  iron,  and  then  passed  through 
a  solution  of  yellow  prussiate  of  potash;  but  this  mode  is  ob- 
jectionable for  light  shades  and  light  goods,  as  it  causes  much 
loss  of  the  Prussian  salt.  The  general  method  of  dyeing  light 
Prussian  blues  upon  cloths  is,  to  put  a  little  nitrate  of  iron  into 
a  vessel  full  of  water ;  the  cloth  is  wrought  in  this  for  about 
ten  or  fifteen  minutes,  and  then  washed  through  two  or  three 
tubs  full  of  clean  water,  to  take  off  all  the  superfluous  acid 
and  iron.  Whether  the  cause  of  the  reception  of  the  dye  be 
an  attraction  of  the  material  of  the  cloth  for  the  iron,  or  the 
simple  power  of  absorption  of  the  fibres,  we  shall  not  stay  to 
examine  here;  but  although  the  nitrate  of  iron  is  an  exceed- 
ingly soluble  salt,  a  portion  of  the  peroxide  of  iron  remains 


—  Zinc 
Protoxide  of  Tin 
Peroxide  of  Tin 


.  White. 
.  White. 
.  Yellow. 


PRUSSIAN  BLUE. 


121 


fixed  in  the  fibres,  having  abandoned  its  acid,  and  this  no  wash- 
ing will  remove.  The  cloth,  being  well  washed  from  the  acid, 
is  put  into  the  prussiate.  A  small  quantity  of  acid  must  be 
added  to  the  ferrocyanide  of  potassium  solution,  to  take  up  the 
potassium,  and  to  set  the  ferrocyanogen  at  liberty,  to  unite  with 
the  iron  upon  the  cloth  ;  this  forms  ferrocyanide  of  iron,  or 
Prussian  blue,  and  constitutes  the  dye.  Considerable  care 
ought  to  be  taken  in  adding  acid  to  the  prussiate,  otherwise 
the  color  is  liable  to  change,  becoming  gray  or  reddish  when 
dried. 

The  following  mode  of  adding  sulphuric  acid  to  the  prus- 
siate/ when  a  considerable  quantity  of  goods  are  to  be  dyed  at 
once,  is  commonly  practised.  What  is  considered  the  proper 
quantity  of  yellow  prussiate  of  potash  is  dissolved  in  just  as 
much  boiling  water  as  is  necessary  for  solution.  To  this  solu- 
tion a  quantity  of  sulphuric  acid  is  added,  sufficient  to  make 
it  strongly  acid  ;  and  the  mixture  thus  prepared  is  added  to  the 
prussiate  tub  as  required.  This  method  of  adding  the  sulphuric 
acid  is  exceedingly  objectionable,  as  it  causes  the  evolution  of 
prussic  acid,  which  may  be  detected  by  the  pungent  smell  it 
excites;  and  in  proportion  to  the  escape  of  that  gas,  there  is  a 
loss  of  the  dyeing  power  of  the  prussiate.  If  three  parts  of 
acid  be  added  to  seven  of  yellow  prussiate,  the  loss  would 
amount  to  one-half,  and  the  remaining  half  would  be  so  changed 
in  its  properties  as  to  produce  only  a  bad  blue.  Thus  the 
dyer  must  use  an  additional  quantity  of  prussiate,  and  after 
all  he  produces  but  an  indifferent  color. 

The  proper  method  of  using  the  acid  is  to  dissolve  the  prus- 
siate in  hot  water,  and  to  add  the  necessary  quantity  of  this 
solution  to  the  water-tub  in  which  the  goods  are  to  be  dyed. 
Previously  to  putting  in  the  cloth,  a  few  drops  of  sulphuric 
acid  are  added,  just  sufficient  to  be  perceptible  to  the  taste;  or, 
what  is  a  much  better  test,  sufficient  to  redden  blue  litmus  paper. 
The  goods  being  wrought  for  some  time  in  this  mixture,  they 
are  washed  in  clean  water,  having  a  small  quantity  of  alum  in 
solution.  For  light  shades  of  sky-blue,  they  should  not  be 
dried  from  the  alum  solution,  as  there  is  a  great  tendency  to 
assume  a  lavender  hue.  A  better  plan  is  to  employ  two  tubs 
of  water,  the  one  being  touched  with  alum,  and  the  other  pure, 
for  washing  from  it.  Cloths  dyed  by  the  prussiate  should  be 
exposed  to  a  very  dry  atmosphere  when  hung  up  to  be  dried. 

Deep  blue  is  dyed  by  passing  the  goods  through  strong  ni- 
trate of  iron,  then  through  potash  lye,  which  fixes  the  oxide  of 
iron  upon  the  cloth,  and  then  through  the  prussiate. 

Eoyal  blue  is  dyed  by  adding  protochloride  of  tin  (salts  of 
tin)  to  the  nitrate  of  iron  ;  entering  the  goods  immediately,  and 


122 


FERRICYANIDE  OF  POTASSIUM. 


passing  them  from  the  iron  through  the  prussiate  without  wash- 
ing. This  method  gives  a  rich  deep  blue,  and  is  now  much 
practised.  Some  of  the  peculiarities  of  the  process  will  here- 
after be  described ;  meantime,  it  will  be  sufficient  to  observe, 
that  a  peculiar  purple  bloom  is  given,  by  using  hydrochloric 
acid  in  the  prussiate  solution  instead  of  sulphuric  acid. 

Ferricyanide  of  Potassium. — This  is  the  red  prussiate  of 
potash.  If  a  current  of  chlorine  gas  be  passed  through  a  strong 
solution  of  yellow  prussiate  of  potash,  till  the  solution  changes 
to  a  reddish  color,  and  when  a  drop  of  it  added  to  nitrate  of 
iron  gives  no  precipitate,  there  is  formed  chloride  of  potassium, 
and  a  salt  differing  materially  from  yellow  prussiate.  The  solu- 
tion being  evaporated,  this  salt  is  obtained  in  beautiful  ruby- 
red  crystals,  termed,  from  their  color,  red  prussiate  of  potash. 
They  are  anhydrous,  soluble  in  4  parts  of  cold  and  a  less 
quantity  of  hot  water.  The  red  prussiate  is  well  adapted  for 
many  operations  in  dyeing,  but  it  is  too  expensive  for  general 
use.  It  yields  the  following  colors  with  the  salts  of  the  differ- 
ent metals  undernamed : — 

Bismuth   Pale  yellow. 

Cadmium   Yellow. 

Cobalt   Dark-brown  red. 

Copper   Yellowish-green. 

Protosalts  of  iron     .    .  Deep  blue. 

Persalts  of  iron    .    .    .  No  precipitate. 

Manganese   Brown. 

Mercury   Red -brown. 

Nickel   Yellowish-brown. 

Tin   White. 

Zinc   Orange-yellow. 

It  will  be  observed  from  this  table,  that  the  salts  of  iron, 
which  yield  a  blue  with  yellow  prussiate  of  potash,  give  no 
color  with  the  red  prussiate;  and  the  protosalts  of  iron,  which 
give  only  a  gray  with  yellow  prussiate,  yield  a  deep  blue  with 
red  prussiate. 

The  true  constitution  of  this  salt,  or  rather  the  arrangement 
in  which  these  elements  unite,  is  still  subject  of  hypothesis. 
We  have  seen,  in  regard  to  the  ferrocyanide,  that  the  iron 
exists  as  a  protocyanide,  with  two  cyanides  of  another  metal ; 
but  in  the  ferricyanide  we  have  iron  as  a  percyanide,  with 
cyanides  of  other  metals.    Thus: — 

Ferrocyanide    .    .  Fe  Cy  +  2  Cy  K  =  Protocyanide. 
Ferricyanide    .    .  Fe2  Cy3  +  3  Cy  K  ==  Percyanide. 

Those  who  suppose  that  the  compound  Fe  Cy3  of  the  yellow 
prussiate  forms  the  salt  radical  of  all  the  ferrocyanides,  suppose 


SODIUM. 


123 


also  that  the  red  prussiate  has  Fe2  Cy6,  consisting  of  the  same 
number  of  elements  combined  together  in  double  proportions, 
corresponding  to  the  pro  and  per  oxides  of  iron.  But  whatever 
may  be  the  true  relation  in  which  the  elements  are  united,  the 
two  salts  are  distinct  in  their  reactions,  and  we  would  suggest 
to  the  dyer  to  give  particular  attention  to  the  difference  of  the 
salts,  with  reference  to  salts  of  iron,  as  they  are  important,  and 
will  be  referred  to  hereafter. 

Cyanide  of  Potassium. — If  yellow  prussiate  be  dried  at  a 
heat  of  about  220°  to  300°,  and  8  parts  of  this  dried  salt  be 
mixed  with  3  parts  of  dry  carbonate  of  potash  and  the  mix- 
ture put  into  a  crucible,  and  fused  until  effervescence  ceases, 
then  removed  from  the  fire,  and  allowed  to  settle  for  a  few 
minutes ;  by  pouring  off  the  clear  into  an  iron  vessel,  it  solidi- 
fies into  a  white  crystalline  mass,  which  is  cyanide  of  potas- 
sium =  Cy  K.  This  salt  has  a  strong  alkaline  reaction,  and 
is  peculiar  for  its  power  of  dissolving  metals  and  giving  pre- 
cipitates which  might  be  advantageously  applied  to  some  of  the 
operations  of  dyeing. 

Cyanate  of  Potash. — This  salt  is  prepared  in  the  same 
way  as  the  last,  but  with  the  addition  of  some  oxide  of  man- 
ganese, or  other  oxide,  which  converts  the  cyanogen  into 
cyanic  acid,  and  forms  cyanate  of  potash  =  Cy  O,  KO.  The 
cyanates  of  the  alkalies  are  all  soluble  in  water,  and  in  this 
they  differ  from  the  cyanates  of  the  other  metals. 

Sodium  (Na  23). 

Soda  was  not  distinguished  from  potash  till  near  the  middle 
of  the  eighteenth  century,  when  their  distinctive  characters 
were  recognized.  The  potash  was  termed  the  vegetable,  and 
the  soda  the  mineral  alkali.  In  1807,  Sir  H.  Davy  demon- 
strated that  soda,  like  potash,  is  the  oxide  of  a  metal  which 
he  named  sodium.  It  is  a  white  metal,  having  much  the 
appearance  of  silver,  but  is  sufficiently  soft  to  yield  to  the 
pressure  of  the  fingers,  and  to  be  cut  by  the  nail.  It  oxidates 
spontaneously  in  the  air,  but  not  so  rapidly  as  potassium. 
When  a  small  piece  is  thrown  upon  water,  it  floats  ;  the  heat, 
generated  by  combining  with  the  oxygen  of  the  water,  melts 
it,  and  it  forms  a  silvery  globe,  which  gyrates  rapidly  on  the 
surface  of  the  water;  but  it  does  not  inflame  the  hydrogen 
unless  it  be  kept  stationary,  and  then  an  explosion  takes  place. 
If,  however,  the  temperature  of  the  water  is  as  high  as  110° 
Fah.,  the  hydrogen  burns  as  it  is  evolved,  with  a  bright  flame. 
In  these  experiments,  oxide  of  sodium  is  formed,  and  dissolved 


124 


SODA. 


in  the  water,  which  thus  becomes  a  solution  of  caustic  soda. 
Sodium  is  a  very  abundant  element  in  nature,  but  is  always 
found  in  combination,  e.  g.  as  nitrate  of  soda  and  chloride  of 
sodium  (common  salt).  This  last  is  the  great  source  of  soda 
for  manufacturing  purposes;  and  since  the  process  of  making 
soda  from  it  was  discovered,  this  alkali,  owing  to  its  cheapness, 
has  been  used  instead  of  potash  in  almost  all  the  processes  of 
the  arts  that  admit  of  the  substitution. 

Soda,  as  sold  to  dyers  and  bleachers,  is  in  the  state  of  a  dry 
white  powder,  or  granular  substance,  termed  soda-ash,  which  is 
an  impure  carbonate  prepared  as  follows:  A  quantity  of  about 
600  lbs.  of  common  salt  is  put  upon  the  bottom  of  a  reverbe- 
ratory  furnace,  previously  heated ;  upon  this  is  let  down,  from 
an  apparatus  on  the  roof  of  the  furnace,  a  quantity  of  sulphuric 
acid,  of  the  specific  gravity  1.600;  and  the  salt  is  decomposed. 
The  result  is  as  follows: — 


The  hydrochloric  acid  passes  off  with  the  steam  occasioned  by 
the  dilute  sulphuric  acid.  This  operation,  during  which  the 
materials  require  to  be  stirred  occasionally,  lasts  about  four 
hours;  the  charge  is  then  withdrawn  from  the  furnace.  The 
sulphate  of  soda  thus  prepared  is  reduced  to  powder,  and 
mixed  with  an  equal  weight  of  ground  chalk,  and  half  its 
weight  of  coal,  well  ground  and  sifted.  This  mixture  is  intro- 
duced into  a  very  hot  reverberatory  furnace,  about  two  hun- 
dred weight  at  a  time,  and  is  frequently  stirred  until  it  is 
uniformly  heated.  In  about  an  hour  it  fuses;  it  is  then  well 
stirred  for  about  five  minutes,  and  drawn  out  with  a  rake  into 
a  cast-iron  trough,  in  which  it  is  allowed  to  cool  and  solidify. 
This  is  called  ball-soda,  or  British  barilla,  and  contains  about 
22  per  cent,  of  alkali.  To  separate  the  salts  from  insoluble 
matter,  the  cake  of  ball-soda,  when  cold,  is  broken  up,  put 
into  vats,  and  covered  by  tepid  water.  In  six  hours,  the  so- 
lution is  drawn  off' from  below,  and  the  washing  repeated  about 
eight  times,  to  extract  all  the  soluble  matter.  These  liquors 
being  mixed  together,  are  boiled  down  to  dryness,  and  afford 
a  salt  which  is  principally  carbonate  of  soda,  with  a  little  caustic 
soda  and  sulphuret  of  sodium.  For  the  purpose  of  getting  rid 
of  the  sulphur,  the  salt  is  now  mixed  with  one-fourth  of  its 
bulk  of  saw-dust,  and  exposed  to  a  low  red  heat  in  another  re- 
verberatory furnace  for  about  four  hours,  which  converts  the 
caustic  soda  into  carbonate,  when  the  sulphur  is  carried  off. 


Common  salt.. 
Sulphuric  acid 


Hydrochloric  acid. 


Sulphate  of  soda. 


SODA-ASH. 


125 


This  product,  if  the  process  is  well  conducted,  contains  about 
50  per  cent,  of  alkali,  and  forms  the  soda-ash  of  the  best  quality. 
When  it  is  to  be  converted  into  crystallized  carbonate  of  soda, 
it  is  dissolved  in  water,  allowed  to  settle,  and  the  clear  liquid 
boiled  down  until  a  pellicle  appears  on  its  surface.  The  solu- 
tion is  then  run  into  shallow  boxes  of  cast-iron  to  crystallize 
in  a  cool  place,  and,  after  standing  for  a  week,  the  mother 
liquor  is  drawn  off,  and  the  crystals  drained  and  broken  up  for 
the  market.  This  mother  liquor  is  evaporated  to  dryness,  and 
yields  a  very  impure  soda-ash,  containing  about  30  per  cent, 
of  alkali,  which  is  often  employed  for  making  soap. 

The  common  crystallized  carbonate  of  soda  of  the  shops  is 
very  pure,  but  is  crystallized  with  10  equivalents  of  water. 
When  exposed  to  the  air,  these  crystals  lose  a  portion  of  their 
water,  and  assume  a  chalky,  white  appearance;  if  they  are  sub- 
jected to  heat,  they  melt  in  their  water  of  crystallization.  We 
have  known  these  crystals  used  for  the  operations  of  bleaching 
merely  dissolved ;  but  they  are  neither  good  nor  profitable, 
used  in  this  way. 

They  contain  in  100  parts  by  weight, 

Caustic  soda  21.81 

Carbonic  acid  15.43 

Water  62.76 


100.00 

Thus  fully  more  than  three-fifths  of  their  weight  is  water. 

The  dry  carbonate  of  soda  of  the  shops,  so  much  used  for 
domestic  purposes,  is  the  same  as  the  crystallized  soda  de- 
prived of  its  water  of  crystallization. 

Soda-Ash. — Owing  to  various  circumstances  attending  the 
manufacture  of  this  salt,  its  percentage  is  very  uncertain, 
varying  from  40  to  50  per  cent.,  and  it  is,  therefore,  generally 
priced  according  to  its  percentage.  The  percentage  may  be 
determined  by  some  such  means  as  we  have  described  for 
bleaching  powder,  that  is,  by  having  an  acid  exactly  of  the 
strength  at  which  100  measures  of  it  will  saturate  100  grains  of 
caustic  soda.  To  form  the  test  acid,  according  to  Professor  Gra- 
ham's directions,  4  ounces  avoirdupois  of  oil  of  vitriol  are 
diluted  with  20  ounces  of  water,  or  larger  portions  of  acid  and 
water  may  be  mixed  in  these  proportions.  About  three-fourths 
of  an  ounce  of  bicarbonate  of  soda  is  heated  strongly  by  a 
lamp  for  a  few  minutes  to  obtain  pure  carbonate  of  soda  (or, 
what  will  do,  take  some  crystals  of  soda  and  dry  in  a  basin 
until  all  the  water  is  given  off;  when  boiling  has  ceased,  make 
the  heat  to  about  a  dull  red ;  this  will  give  the  soda  salt),  of 


126 


TESTING  SODA-ASH. 


which  171  grains  are  immediately  weighed,  that  quantity  con- 
taining 100  grains  of  soda;  this  portion  of  carbonate  of  soda 
is  dissolved  in  4  or  5  ounces  of  hot  water,  and  the  alkalimeter 
is  filled  up  to  the  highest  graduation  with  the  dilute  acid. 
The  acid  is  poured  gradually  into  the  soda  solution  till  the 
action  of  the  latter  upon  blue  litmus  test-paper  ceases  to  be  al- 
kaline and  becomes  distinctly  acid,  and  the  measures  of  acid 
necessary  to  produce  that  change  are  accurately  observed;  say 
it  requires  90  measures.  A  plain  cylindrical  jar,  of  which  the 
capacity  is  about  a  pint  and  a  half,  is  graduated  into  100  parts, 
each  containing  100  grain  measures  of  water,  or  ten  times  as 
much  as  the  divisions  of  the  alkalimeter.  This  jar  is  filled  up 
with  dilute  acid  to  the  extent  of  90,  or  whatever  number  of  the 
alkalimeter  divisions  of  acid  were  found  to  neutralize  100 
grains  of  soda,  and  water  is  added  to  make  up  the  acid  liquid 
to  100  measures.  This  forms  a  test  acid  of  which  100  mea- 
sures neutralize  and  are  equivalent  to  100  grains  of  soda,  or 
one  measure  of  acid  to  one  grain  of  caustic  soda.  This  acid 
ought  to  be  kept  in  a  well  stoppered  bottle.  By  a  curious  coin- 
cidence, strong  oil  of  vitriol  diluted  with  11  times  its  weight 
of  water,  gives  this  test  acid  exactly;  but,  as  oil  of  vitriol 
varies  a  little  in  strength,  it  is  better  to  form  the  test  acid  in 
the  manner  described,  than  to  trust  to  that  mixture.  Twenty- 
one  measures  of  the  test  acid  should  neutralize  100  grains  of 
crystalized  carbonate  of  soda,  and  68.5  measures  of  it  should 
neutralize  100  grains  of  pure  anhydrous  carbonate  of  soda. 

To  test  a  sample  of  soda-ash,  100  grains  are  weighed  and 
dissolved  in  two  or  three  ounces  of  hot  water.  The  alkalime- 
ter is  filled  with  the  test  acid,  which  is  gently  poured  into 
this  solution,  stirring,  as  each  drop  is  added,  until  a  piece  of 
blue  litmus-paper,  which  may  be  kept  in  contact  with  the 
liquor,  is  turned  red.  The  number  of  graduations  taken  to 
effect  this  indicates  the  percentage  of  caustic  alkali  in  the 
sample. 

Another  method  of  using  test  acid  is  by  weight.  The 
acid  is  made  to  such  a  strength  as  one 
Fig.  11.  or  two  grains  by  weight  will  exactly 

neutralize  one  grain  of  pure  alkali. 
The  vessel  commonly  used  for  this 
purpose  is  of  the  annexed  form,  but 
any  convenient  vessel  will  do.  It  is 
filled  with  the  test  acid,  and  the  whole 
correctly  weighed.  The  acid  is  then 
dropped  from  the  small  orifice  into  a 
weighed  quantity  of  the  carbonate 
until  a  neutral  sulphate  is  produced, 


TESTING  SODA-ASH. 


127 


indicated  as  above  by  test-paper.  The  bottle  with  its  contents 
is  then  again  weighed  ;  the  loss  of  weight  gives,  by  calculation, 
the  quantity  of  real  alkali  in  the  sample.  Say  that  every  two 
grains  of  the  test  acid  are  equivalent  to  one  grain  of  pure  soda, 
and  that  twenty-five  grains  of  soda-ash  require  twenty  grains 
of  acid  to  neutralize  it,  the  real  alkali  present  will  be  ten. 
Now  25  being  the  fourth  of  100,  the  10  is  multiplied  by  4, 
giving  40  as  the  percentage  of  the  sample.  This  method  of 
testing  carbonated  alkalies,  provided  the  operator  has  a  good 
balance,  is  more  correct  than  that  with  the  graduated  tube,  and 
equally  simple. 

Another  very  ready  method,  sometimes  recommended,  is  to 
take  a  small  flask  and  a  test-tube  that  will  go  inside,  and  stand 
nearly  straight.  Fifty  grains  of  the  soda-ash  are  dissolved  in 
a  little  water  in  the  flask,  and  the  tube,  which  is  nearly  filled 
with  sulphuric  acid,  is  carefully  placed  in  the  position  shown 
in  the  figure.  A  small  chloride  of  calcium  tube  is  fitted  into 
the  mouth  of  the  flask,  and  the  whole  is 
then  carefully  weighed;  after  which,  by  Fig.  12. 

holding  the  flask  a  little  on  one  side,  the 
acid  is  poured  from  the  tube  into  the 
soda  solution.  This  should  be  done 
gradually,  that  the  effervescence  may  not 
be  too  violent.  When  all  effervescence 
ceases,  and  the  flask  is  well-shaken,  the 
cork  is  taken  out,  that  the  rest  of  the 
carbonic  acid  may  freely  escape;  it  is 
then  put  back,  and  the  flask  is  again 
weighed ;  the  loss  of  weight  will  of 
course  indicate  the  loss  of  carbonic  acid,  and  by  this  the  quan- 
tity of  soda  present  may  be  calculated.  If  the  loss  of  weight 
be  ten  grains,  then  as  22  the  equivalent  of  carbonic  acid,  is  to 
31  that  of  soda,  so  is  10  to  14.09,  which,  being  multiplied  by 
2,  there  being  only  50  grains  of  soda  used,  gives  28.18  as  the 
percentage  of  alkali  in  the  sample.  This  method,  however,  is 
not  much  to  be  relied  upon  in  testing  the  value  of  alkali. 

There  are  a  great  many  other  modes  of  proceeding,  all  em- 
bracing the  same  principles  as  those  detailed,  and  also  a  great 
variety  of  apparatus  for  the  purpose,  but  it  is  needless  to  men- 
tion them. 

It  will  be  observed  that  the  same  principle  applies  to  pot- 
ash as  to  soda.  In  the*  process  where  the  loss  of  carbonic  acid 
is  made  the  criterion,  the  difference  is  in  the  equivalents.  The 
equivalent  of  potash  being  47.2,  the  proportion  becomes 
22  :  47.2  :  :  10  x  2  :  21.45  X  2  =  42.9  per  cent.  With  the 
test  acid  process,  there  may  be  obtained  an  acid  of  such 


128 


TESTING  SODA-ASH. 


strength  that  one  graduation  will  be  equal  to  one  grain  of  potash, 
which  will  be  found  in  the  same  way  as  for  soda,  namely,  by 
neutralizing  a  known  weight  of  pure  dry  carbonate  of  potash. 

The  operation  most  frequently  tried,  is  performed  by  neu- 
tralizing a  given  quantity  of  acid,  which  does  for  either  soda 
or  potash. — Prepare  a  little  pure  anhydrous  carbonate  of  soda 
as  described  for  the  soda  test ;  weigh  53  grains,  which  is  an 
equivalent,  and  dissolve  in  water ;  then  take  dilute  acid  in 
the  alkalimeter,  and  add  it  to  the  soda  until  it  is  perfectly  neu- 
tral; mark  the  number  of  graduations  it  takes  for  this ;  say  it 
takes  30 ;  then  to  every  30  of  the  acid  add  70  of  water,  and 
thus  we  have  a  stock  acid,  of  which  100  graduations  is  equal 
to  an  equivalent  of  any  alkali.    Thus — 

100  graduations  is  equal  to  31  grains  caustic  soda, 

47.2    "       "  potash, 
17      "       "  ammonia, 
28      "       "  lime. 

To  test  by  this  method,  take  100  graduations  of  the  test  acid, 
and  weigh  100  grains  of  the  alkali,  and  dissolve  in  100  mea- 
sures of  water  ;  add  this  solution  to  the  acid  till  it  is  neutral- 
ized, and  mark  how  many  measures  have  been  necessary  to 
effect  this ;  then  the  percentage  of  alkali  is  easily  calculated. 
Say  that  70  measures  of  the  alkali  solution  have  been  necessary 
to  neutralize  the  acid  ;  if  the  alkali  is  soda,  then  the  70  grains 
of  soda-ash  will  contain  31  grains  of  caustic  soda ;  and  the 
percentage  is  found  by  the  following  calculation  : — 

70  :  31  :  :  100  :  44.3  per  cent. 

If  the  alkali  is  carbonate  of  potash,  the  70  grains  will  contain 
47.2  grains  of  caustic  potash ;  and  then  the  percentage  is  found 
by  the  proportion  : — 

70  :  47.2  :  :  100  :  67.45  per  cent. 

For  commercial  salts,  either  of  potash  or  soda,  the  mode  of 
testing  by  neutralizing  is  preferable  to  that  which  depends  on 
calculating  from  the  loss  of  carbonic  acid,  as  there  are  some- 
times portions  of  caustic  alkali  in  the  sample  which  the  car- 
bonic acid  process  will  not  indicate. 

It  may  also  be  observed  that  the  acid  test  for  soda,  derived 
from  a  coincidence  in  their  equivalents,  will  serve  equally  well 
for  potash,  each  graduation  being  about  1  of  caustic  soda,  and 
1J  of  potash. 

The  process  for  making  caustic  soda  from  soda-ash,  is  the 
same  as  described  for  making  caustic  potash,  namely,  a  quan- 
tity of  ash  is  boiled,  and,  when  boiling,  slaked  lime  is  added 


SULPHATE  OF  SODA. 


129 


until  a  small  portion  taken  out  does  not  effervesce  on  adding 
an  acid  ;  but  the  equivalent  of  soda  being  less  than  that  of  pot- 
ash, it  requires  more  lime  for  a  given  weight. 

The  following  table,  constructed  by  Dr.  Dalton,  will  be  found 
useful  to  the  operative  bleacher,  showing  the  quantity  of  caustic 
soda  in  his  solutions,  indicated  by  the  hydrometer : — 


Specific 

Alkali 

Twaddell's 

Specific 

Alkali 

Twaddell's 

gravity. 

per  cent. 

hydrometer. 

gravity. 

per  cent. 

hydrometer. 

2.00 

77.8 

200 

1.40 

29.0 

80 

1.85 

63.6 

170 

1.36 

26.0 

72 

1.72 

53.8 

144 

1.32 

23.0 

64 

1.63 

46.6 

126 

1.29 

19.0 

58 

1.56 

41.2 

112 

1.23 

16.0 

46 

1.50 

36.8 

100 

1.18 

13.0 

36 

1.47 

34.0 

94 

1.12 

9.0 

24 

1.44 

31.0 

88 

1.06 

4.7 

12 

The  remarks  (page  117)  in  reference  to  the  presence  of 
sulphurets  in  potash-lye  injuring  the  gold  ornaments  of  light 
muslins,  &c,  are  equally  applicable  here;  and  the  same  tests 
for  ascertaining  the  presence  of  these  impurities  in  potash  may 
be  employed  to  detect  their  presence  in  soda  solutions.  With 
respect  to  the  solubility  of  soda: — 

100  parts  water,  at  62° 
100  "  90° 

100  "  131° 

100  "  158° 

100         "  176° 

Cold  water,  saturated  with  soda,  and  brought  to  a  boil,  attains 
a  temperature  of  266°  Fah. 

The  salts  of  soda  are  in  general*  the  same  in  their  chemical 
characters  as  the  corresponding  salts  of  potash,  but  they  are 
not  so  generally  used,  on  account,  perhaps,  of  the  disposition 
which  almost  all  soda  salts  have  to  effloresce  when  exposed  to 
the  air. 

Sulphate  of  Soda. — Soda  saturated  with  sulphuric  acid, 
forms  sulphate  of  soda,  which  crystallizes  easily,  and  is  known 
by  the  name  of  Glauber  Salts.  A  dry  and  impure  sulphate 
of  soda  is  sold  under  the  name  of  salt  cake ;  it  is  obtained  by 
heating  common  salt  and  sulphuric  acid  in  making  hydrochloric 
acid.  It  commonly  contains  about  one-third  of  its  weight  of 
salt.    A  purer  sort  of  salt  cake  is  obtained  by  the  makers  of 


Fah.  dissolve  41  parts  of  caustic  soda. 
"  64 

"  72  " 
u         78  « 


130 


LITHIUM. 


nitric  acid  ;  in  this  process,  the  nitrate  of  soda  is  acted  upon 
by  sulphuric  acid,  and  the  product  being  valuable,  considerable 
care  is  taken  to  have  the  nitrate  decomposed.  We  have  seen 
salt  cake,  from  this  source,  containing  as  much  as  98  per  cent, 
of  sulphate  of  soda. 

Chloride  of  Sodium. — Hydrochloric  acid,  added  to  soda, 
forms  hydrochlorate  of  soda  (muriate  of  soda) — more  properly 
chloride  of  sodium  (common  salt).    The  action  is  as  follows : — 


Hydrochloric  acid    j  H ;  Water 

This  salt  is  sometimes  employed  with  nitric  acid  to  make 
the  aqua  regia  used  for  dissolving  tin.  It  is  often  amusing  to 
see  the  care  taken  to  mix  the  acid  and  the  soda  to  form  what 
may  be  got  so  conveniently  as  common  salt. 

Nitrate  of  Soda.— Nitric  acid,  added  to  soda,  forms  nitrate 
of  soda.  This  salt,  as  already  stated  (page  62),  is  found 
abundantly  in  nature,  and  is  termed  cubic  nitre,  from  the  shape 
of  its  crystals,  and  to  distinguish  it  from  nitrate  of  potash 
{nitre).  When  heated  to  redness,  it  is  decomposed,  and  gives 
off  much  oxygen  gas ;  it  is  often  employed  for  this  purpose, 
and  for  oxidizing  metals  in  a  fused  state.  It  is  also  occasion- 
ally used  for  preparing  some  of  the  salts  of  tin  for  mordants, 
along  with  hydrochloric  acid. 

Borate  of  Soda. — Boracic  acid,  with  soda,  forms  borate 
of  soda  [borax  or  tinkal).  This,  as  we  have  before  noticed, 
(under  Boron),  is  also  a  natural  product;  it  is  used  as  a  blow- 
pipe reagent  for  fluxing  metals. 

Phosphate  of  Soda. — Phosphoric  acid,  with  soda,  forms 
phosphate  of  soda,  also  a  useful  salt,  as  a  test  for  the  presence 
of  magnesia  in  water  solutions. 

Soda,  on  account  of  its  cheapness,  has  been  substituted  for 
potash  in  the  manufacture  of  some  of  the  salts  most  extensively 
used,  such  as  ferrocyanides,  chromates,  alum,  &c,  but  none 
of  these  modified  salts  have  come  into  common  use,  not  that 
they  are  less  suitable  in  the  dye-house,  but  for  other  reasons 
which  we  need  not  here  examine. 


Soda,  Na 


Chloride  sodium. 


Lithium  (L  6.5). 


This  is  another  alkaline  metal,  the  oxide  of  which  is  termed- 
Lithia.  It  has  properties  somewhat  resembling  those  of  soda 
and  potash,  and  combines  with  acids  as  a  base  in  the  same  man- 


SOAP. 


131 


ner  as  these  other  alkalies.  It  is,  however,  very  rare,  and  only 
got  in  small  quantities,  from  a  mineral  termed  Lepidolite.  It 
has  not,  as  yet,  been  used  in  any  process  of  manufacture,  and 
has  therefore  no  claim  to  our  farther  consideration. 

Soap. 

In  connection  with  the  alkalies,  it  will  be  necessary  to  direct 
attention  to  Soap,  an  article  of  great  importance  in  the  dye- 
house.  If  we  take  a  quantity  of  oil,  and  add  to  it  some  caus- 
tic alkali,  a  milk-white  solution  is  obtained,  which  is  found  to 
be  soluble  in  water.  This  solution,  boiled  down  to  a  proper 
consistence  and  cooled,  forms  soap.  All  sorts  of  fats  and  oils 
are  used  in  soap-making  ;  they  all  contain  certain  acids,  capable 
of  combining  with  the  alkali,  and  giving  a  detersive  character 
to  the  compound.  The  soap  made  with  soda  is  hard,  that  with 
potash  soft;  and  the  degree  of  hardness,  in  either  case,  varies 
according  to  the  nature  of  the  oil  or  fat  employed.  In  manu- 
facturing soap,  care  is  taken  to  obtain  a  proper  mixture  of 
these  fats  and  oils,  so  as  to  produce  a  soap  of  proper  consist- 
ence. The  following  extract  on  this  subject  from  Normandy's 
Commercial  Handbook  of  Chemical  Science,  is  important: — 

*  Mottled  soap  has  a  marbled  or  streaky  appearance ;  that 
is  to  say,  veins  of  a  bluish  or  slate  color  pervade  its  mass, 
which  is  white  or  whitish;  the  size  and  number  of  these  veins 
depend  on  the  more  or  less  rapid  cooling  of  the  soap  after  it 
has  been  transferred  from  the  copper  to  the  frames.  The  blue 
or  slate  color  of  these  streaks  is  chiefly  due  to  the  presence  of 
an  alumino-ferruginous  soap  interposed  in  the  mass,  and  fre- 
quently, also,  to  that  of  sulphuret  of  iron,  which  is  produced 
by  the  reaction  of  the  alkaline  sulphurets,  contained  in  the 
soda-lye,  upon  the  iron,  derived  from  the  iron,  copper,  and 
utensils  employed  in  this  manufacture,  or,  which  even  is,  at 
times,  introduced  purposely  as  sulphate  of  iron.  The  veins 
gradually  disappear  from  the  surface  to  the  centre,  by  keeping, 
by  the  oxidation  of  the  sulphuret  of  iron.  A  well  manufac- 
tured mottled  soap  cannot  contain  more  than  33,  34,  or,  at 
most,  36  per  cent,  of  water.  The  addition  of  water  causes  the 
color  to  subside,  and  a  white  soap  is  produced.  This  addition 
of  water  is  made  when  the  object  is  to  give  white  soap ;  so 
that,  with  this  additional  quantity  of  water,  white  soap  some- 
times contains  55  per  cent.  It  is  therefore  best  to  buy  mot- 
tled soap  in  preference  to  yellow  or  white  soap,  the  mottling 
being  a  sure  criterion  of  genuineness,  as  the  addition  of  water 
or  other  matters  would  soon  destroy  the  mottling." — This 


132 


SOAP. 


quality  of  soap  is  not  much  known  in  Scotland ;  even  the  name 
is  not  used.  "  To  yellow  or  white  soap,"  says  Mr.  Normandy, 
i£  incredible  quantities  of  water  may  be  added.  I  have  known 
15  gallons  of  water  added  to  a  frame  of  already  fitted  soap  (10 
cwt.),  so  that  the  soap,  after  this  treatment,  contained  upwards 
of  60  per  cent,  of  water.  Common  salt  had  been  previously 
dissolved  in  the  liquor. 

"Besides  being  surcharged  with  water,  soap  is  sometimes 
farther  adulterated  with  gelatin,  made  by  boiling  bones, 
sinews,  hoofs,  skins,  fish,  &c.;  in  alkalies;  also  with  dextrine, 
potato-starch,  pumice-stone,  silica,  plaster  of  Paris,  clay,  salt, 
chalk,  carbonate  of  soda,  &c.  &c." 

Soft,  or  black  soap,  is  the  most  useful  of  all  the  soaps.  It  is 
made  with  fats  or  oils  and  a  solution  of  potash,  and  always 
contains  a  great  excess  of  alkali'  and  much  water ;  also  chlo- 
rides, sulphates,  and  other  impurities.  Fish  oil  is  also  often 
employed  in  the  making  of  this  soap,  which  gives  it  a  very 
disagreeable  smell.  Soft  soap,  which  has  a  greenish  color,  is 
best,  although  occasionally  this  color  is  given  to  a  very  inferior 
article,  by  the  addition  of  a  little  indigo. 

The  quantity  of  water  in  soap  may  be  ascertained  by  taking 
100  grains  of  the  sample  in  thin  parings,  putting  them  into  a 
water-bath  or  oven,  of  which  the  heat  does  not  exceed  212°, 
and  allowing  them  to  stand  as  long  as  they  continue  to  lose 
weight,  which  is  known  by  occasional  weighing;  the  loss  of 
weight  indicates  the  water  evaporated.  In  mottled  soap,  it 
should  not  exceed  35  per  cent. ;  in  the  white  and  yellow  soaps, 
it  ought  not  to  be  more  than  50  per  cent. 

The  other  impurities  of  soap  may  be  detected  by  dissolving 
100  grains  in  strong  alcohol,  and  applying  a  gentle  heat ;  the 
soap  is  thus  dissolved,  and  the  impurities  remain  as  precipitate. 
The  best  soap  should  not  contain  above  1  per  cent,  of  matter 
insoluble  in  alcohol.  Good  soap  may  be  known  by  its  com- 
parative transparency.  When  cut  thin,  the  purer  the  soap  is 
the  more  translucent.  Dry  soap  is  also  more  transparent  than 
wet. 

The  earths  combine,  also,  with  fats  and  form  soaps,  some  of 
which  are  difficultly  soluble  in  water,  so  that  if  there  be  oil 
or  grease  upon  goods,  and  they  are  put  into  matters  that  form 
an  insoluble  or  difficultly  soluble  soap,  these  spots  will  be  so 
many  white  stains  in  the  dyed  goods ;  and  when  ordinary  soap, 
made  from  fats,  is  put  into  water  that  has  earthy  matters  or 
salts  in  it,  these  salts  are  decomposed  by  the  alkali  of  the  soap 
taking  the  acid,  and  greasy  or  insoluble  soapy  spots  are  pro- 
duced. This  is  often  experienced  in  washing  with  soap  in  hard 
water;  these  spots  are  sources  of  annoyance  to  the  dyer. 


SOAP. 


133 


When  soap  is  dissolved  in  water,  there  should  be  no  oily  or 
fatty  matter  visible  on  the  surface,  as  this  would  indicate  that 
too  little  alkali  had  been  used  in  the  manufacture  of  the  soap. 
The  following  method  of  testing  the  quality  of  soaps  is  given 
by  M.  Dumas,  in  the  Chimie  Appliquee  aux  Arts,  tome  vi. : — 

"To  determine  the  quantity  of  water,  thin  slices  are^ut 
from  the  edges  and  from  the  centre  of  the  bars.  A  portion  is 
then  weighed,  about  60  to  70  grains,  and  exposed  to  a  current 
of  air,  heated  at  212°  F.,  or  in  an  oil-bath,  until  it  ceases  to 
lose  weight.  The  dry  substance  is  then  weighed  ;  the  difference 
between  the  first  and  last  weighing  will  indicate  the  quantity 
of  water  evaporated.  If  it  be  a  soft  soap,  it  is  weighed  in  a 
counterpoised  shallow  capsule.  In  good  soap,  the  amount  of 
water  varies  from  30  to  45  per  cent.,  in  mottled  and  soft  soaps, 
from  36  to  52  per  cent. 

"The  purity  of  soap  may  be  ascertained  by  treating  it  with 
•  hot  alcohol ;  if  the  soap  be  white,  and  without  admixture,  the 
portion  remaining  undissolved  is  very  minute,  and  a  mottled 
soap  of  good  quality  does  not  leave  more  than  about  1  per 
cent. 

"If  there  should  be  a  sensible  amount  of  residue  from  white 
soap,  or  more  than  1  per  cent,  from  mottled  soap,  some  acci- 
dental or  fraudulent  admixture  may  be  suspected,  silica,  alu- 
mina, gelatin,  &c,  the  quantity  and  nature  of  which  may  be 
determined  by  analysis. 

"The  quantity  of  alkali  contained  in  the  soap  is  easily  de- 
termined by  means  of  the  alkalimeter;  a  known  quantity  of 
the  soap  is  dissolved  in  water,  and  tried  by  the  test  acid. 

"There  is  no  difficulty  in  ascertaining  in  the  same  assay  the 
quantity  of  the  fatty  substance.  For  this  purpose,  150  grains 
of  pure  white  wax,  free  from  water,  are  added  to  the  liquid 
after  saturation  with  the  test  acid,  and  the  whole  heated  to 
complete  liquefaction ;  it  is  then  allowed  to  cool,  and  when  it 
has  become  solid,  the  cake  of  wax  and  fatty  matter  which  have 
united  is  removed  and  washed,  dried,  and  weighed ;  the  aug- 
mentation in  weight  beyond  the  150  grains  employed  will  give 
the  weight  of  the  fatty  matter. 

"  The  liquid  decanted  from  the  solidified  wax  may  after- 
wards be  tested  to  ascertain  the  purity  of  the  base. 

"The  solution  of  the  sulphate  may  also  be  evaporated,  and 
by  an  examination  of  its  crystalline  form,  or  by  means  of  chlo- 
ride of  platinum,  it  may  be  ascertained  whether  the  base  be 
soda  or  potash,  or  a  mixture  of  the  two. 

"  As  to  the  nature  of  the  fatty  substance,  it  is  ascertained, 
with  more  or  less  certainty,  by  saturating  the  solution  of  the 
soap  with  tartaric  acid,  collecting  the  fat  acids,  and  taking  their 


184 


BARIUM. 


point  of  fusion.  It  is  possible,  at  least,  by  this  to  prove  the 
identity,  or  the  absence  of  identity,  with  the  sample  in  the  soap 
supplied ;  for  instance,  whether  it  is  made  from  oil  or  tallow, 
&c.  The  odor  developed  by  the  fatty  acids,  at  the  moment 
of  the  decomposition  of  the  soap  by  acids  assisted  by  heat, 
will  often  indicate  the  nature  of  the  fatty  substance  employed 
in  Its  fabrication,  or  that  at  least  of  which  the  odor  may 
prevail. 

"  The  soap  is  proved  to  contain  an  excess  of  fatty  matter 
not  saponified,  by  separating  the  fatty  acids  by  means  of  hy- 
drochloric acid,  washing  with  hot  distilled  water,  then  com- 
bining them  with  baryta,  and  thoroughly  washing  the  new 
compound  with  boiling  water.  The  non-saponified  fatty  mat- 
ter is  easily  separated  from  the  barytic  soap  by  treating  the 
mass  with  boiling  alcohol,  which  dissolves  the  fatty  substance. 
We  can,  moreover,  assure  ourselves  that  it  has  no  acid  reac- 
tion on  moistened  litmus-paper,  that  it  is  fusible,  and  that  it 
possesses  the  general  characters  of  a  neutral  fatty  substance." 


Barium  (Ba  68.5). 

This  is  a  metal  having  a  silver- white  lustre,  and  considerable 
ductility  ;  it  is  four  times  heavier  than  water,  rapidly  oxidates 
when  exposed  to  the  air,  forming  Barytes,  one  of  those  sub- 
stances termed  earths,  and  which  has  strong  alkaline  properties. 
This  earth,  which  was  decomposed  and  its  metallic  basis  dis- 
covered by  Sir  H.  Davy  in  1808,  exists  abundantly  in  nature, 
in  combination  with  sulphuric  acid,  forming  sulphate  of  barytes 
(heavy  spar),  and  with  carbonic  acid  forming  carbonate  of 
barytes.  The  artificial  salts  are  generally  prepared  from  the 
sulphate,  which  is  ground  fine,  mixed  with  charcoal,  and  kept 
at  a  strong  red  heat  in  a  crucible  for  about  an  hour.  Sulphuret 
of  barium  is  thus  formed.  This  is  now  acted  upon  by  nitric 
or  hydrochloric  acid,  to  form  the  nitrate  or  chloride,  according 
as  one  acid  or  the  other  is  used.  These  salts  may  also  be  ob- 
tained from  the  carbonate  without  previous  heating,  by  merely 
digesting  the  mineral  in  the  acid. 

Chloride  of  Barium  is  a  crystalline  salt,  of  which  100 
parts  of  cold  water  dissolve  about  43  parts. 

Nitrate  of  Barytes  is  also  a  crystalline  salt,  but  not  so 
soluble  in  water ;  100  parts  of  cold  water  dissolve  only  about 
8  J  parts  of  it.  The  affinity  of  barytes  for  sulphuric  acid  is  very 
great ;  it  takes  it  from  every  soluble  substance,  and  forms  with 
it  an  insoluble  precipitate.  Hence  it  is  that  barytes  is  pre-emi- 
nently the  test  for  sulphuric  acid. 


STRONTIUM — CALCIUM. 


135 


The  Acetate  of  Barytes  is  sometimes  used  to  precipitate  the 
sulphuric  acid  of  alum,  and  form  an  acetate  of  alumina;  but 
this  use  of  the  salt  is  not  very  extensive. 

Strontium  (Sr  43.8). 

This  is  a  metal  very  similar  to  Barium  in  appearance  and 
properties.  Its  oxide  is  termed  Strontia.  It  is  another  of  the 
earths  which  has  alkaline  properties,  and  which  occurs  in  na- 
ture in  combination  with  carbonic  and  sulphuric  acids,  although 
not  very  abundantly.  The  artificial  salts  are  prepared  from 
the  carbonate,  by  acting  upon  it  with  nitric  or  hydrochloric 
acid,  by  which  is  formed  nitrate  of  strontia  or  chloride  of 
strontium,  both  crystallizable  salts.  Its  solutions  precipitate 
sulphuric  acid,  but  not  so  fully  as  the  solutions  of  barytes. 
The  salts  of  strontium  are  not  used  in  manufactures,  except 
indeed  for  fireworks;  they  have  the  property  of  communicating 
a  red  color  to  flame. 

Calcium  (Ca  20). 

This  is  a  metal  of  which  the  oxide  is  Lime — one  of  the  most 
widely  diffused  of  all  the  earths,  and  also  one  of  the  most  gene- 
rally useful.  It  exists  in  nature  as  a  carbonate  and  as  a  sul- 
phate. Ordinary  limestone,  chalk,  marble,  &c.  are  carbonates : 
gypsum,  plaster  of  Paris,  &c.  are  sulphates. 

Caustic  Lime  is  obtained  by  heating  the  carbonate  to  red- 
ness— which  is  the  ordinary  process  of  lime-burning  in  a  kiln. 
The  carbonic  acid  is  driven  off,  and  caustic  or  burned  lime 
remains.  The  caustic  lime  combines  rapidly  with  one  equiva- 
lent of  water,  and,  becoming  a  hydrate,  falls  into  a  fine  pow- 
der, commonly  termed  slaked  lime.  During  this  operation, 
much  heat  is  evolved  from  the  water  as  it  passes  from  a  fluid 
to  a  solid  state  in  combining  with  the  lime,  and  gives  out  its 
heat  of  fluidity. 

Lime  is  soluble  in  water,  producing  lime-water,  which  has 
an  alkaline  reaction,  much  valued  in  the  dye  house.  It  takes 
78  gallons  of  water  at  60°  to  dissolve  one  pound  of  lime ;  97 
gallons  at  130° ;  and  127  gallons  at  212°. 

Thus  we  see  that  cold  water  dissolves  more  lime  than  hot 
water ;  so  the  practice  of  putting  boiling  water  into  lime,  in 
order  to  get  a  strong  solution,  is  erroneous ;  and  when  a  boiler 
is  filled  with  cold  lime-water,  and  brought  to  boil,  as  when 
oranges  are  to  be  raised,  we  see  why  there  is  always  a  quantity 
of  powder  deposited ;  for,  as  the  hot  water  does  not  hold  the 


136 


MAGNESIUM. 


same  quantity  of  lime  in  solution  as  the  cold,  the  surplus  is 
deposited  in  fine  crystalline  grains.  Lime-water,  exposed  to 
the  air,  absorbs  carbonic  acid  rapidly,  forming  a  thin  pellicle 
on  the  surface,  which,  falling  down  from  time  to  time,  the  lime 
in  the  solution  will  ultimately  be  all  deposited.  Lime,  in  its 
caustic  state,  is  extensively  used  in  the  dye-house,  and  we  will 
hereafter  have  occasion  to  refer  to  it  when  describing  the 
operations  of  the  trade. 

Lime  combines  with  the  acids,  forming  a  series  of  salts  of 
little  practical  use  to  the  dyer.  With  hydrochloric  acid  it 
forms  the  chloride  of  calcium — a  very  deliquescent  salt,  which 
is  sometimes  on  that  account  used  in  absorbing  moisture  from 
gases,  &c.  It  is  formed  in  the  spontaneous  decomposition  of 
bleaching  powder,  which  it  makes  damp.    (See  page  81.) 

Sulphate  of  Lime  is  an  insoluble  substance,  or  nearly  so, 
the  acid  and  lime  having  a  strong  affinity  for  each  other.  This 
salt  is  formed  in  the  common  blue  vat  by  the  sulphate  of  iron. 
It  is  held  in  solution  in  very  minute  quantities  in  some  spring 
waters. 

Carbonate  of  Lime  [Limestone)  is  soluble  in  water  holding 
carbonic  acid,  probably  forming  a  bicarbonate  of  lime. 

The  best  test  for  the  presence  of  lime  is  a  solution  of  oxalate 
of  ammonia,  which  gives  with  lime  a  white  precipitate. 

Magnesium  (Mg  12). 

This  is  a  silver- white  metal,  ductile  and  hard,  and  oxidates 
rapidly  when  exposed  to  moist  air  and  in  water. 

Magnesia. — The  oxide  is  the  well-known  alkaline  earth 
magnesia,  which,  having  a  low  combining  equivalent,  is  re- 
markable for  its  great  power  of  saturating  acids.  Magnesia  is 
abundant  in  nature,  but  it  is  found  chiefly  in  the  state  of  car- 
bonate. There  are  immense  beds  of  it  in  combination  with 
lime,  termed  magnesian  limestone.  The  carbonate  is  soluble 
in  water,  which  contains  free  carbonic  acid,  and  imparts  to  the 
water  a  slightly  alkaline  reaction.  Magnesia  combines  with 
the  acids,  and  forms  with  them  a  series  of  salts  of  considerable 
importance  in  several  manufactures  and  in  medicine,  but  they 
are  not  much  used  in  dyeing.  The  salt  principally  used  is 
the  sulphate  (Epsom  salt),  which  exists  in  certain  springs,  and 
is  easily  prepared  by  saturating  magnesia  or  carbonate  of  mag- 
nesia, with  sulphuric  acid,  and  evaporating  the  solution  to 
crystallize  the  salt.  Salts  of  magnesia  in  water  are  very  bad 
for  delicate  colors.  The  best  test  for  its  presence  is  phosphate 
of  soda,  with  which,  after  long  stirring,  it  gives  a  white  pre- 
cipitate, even  with  very  minute  quantities. 


ALUMINUM. 


137 


The  five  elements — Glucinum  or  Beryllium,  Yttrium,  Tho- 
rium, and  Aluminum — have  been  termed  the  metals  or  bases 
of  the  earths  proper,  to  distinguish  them  from  the  four  elements 
we  have  just  been  considering;  these,  from  having  alkaline 
properties,  have  been  termed  the  alkaline  earths.  The  first 
named  three  elements  of  the  earths  proper  are  very  rare,  and 
their  characters  have  been  studied  by  very  few  chemists; 
accordingly,  little  is  known  about  them,  and  as  no  practical 
application  has  been  made  of  any  of  them  or  their  salts,  we 
may  dismiss  them  with  this  brief  notice.  But  the  fourth, 
namely,  aluminum,  is  of  vast  importance,  and  consequently 
demands  special  attention. 


Aluminum  (Al  13.7). 

Aluminum  is  a  white  metal,  very  ductile  and  tenacious.  Its 
point  of  fusion  is  below  that  of  silver.  Remarkable  by  its 
low  specific  gravity  (2.56  to  2.67),  this  metal  is  little  acted 
upon  by  oxygen.  Its  true  solvent  is  muriatic  acid ;  nitric  and 
sulphuric  acid  dissolve  it  only  when  hot  and  concentrated. 

Alumina. — There  is  only  one  oxide  of  aluminum  known, 
which  is  a  sesquioxide,  Al2  03.  This  is  termed  alumina, 
which  is  the  pure  plastic  principle  of  clay,  and  is  exceedingly 
abundant  in  nature  as  such.  It  combines  with  acids,  forming 
salts,  but  it  only  combines  in  the  proportions  stated:  thus;  by 
dissolving  alumina  in  hydrochloric  acid  there  is  formed — 

Alumina  .......  ^jj 

3  Proportions  hy-    ( 3  H. 
drochloric  acid     (  3  CI 

Alum. — Alumina  is  easily  dissolved  in  sulphuric  acid,  form- 
ing the  sulphate  of  alumina,  which  crystallizes  with  much 
difficulty ;  but  this  salt  has  a  strong  affinity  for  the  sulphate 
of  potash;  so  that  when  these  two  salts  are  mixed,  or  when  a 
salt  of  potash  is  added  to  a  strong  solution  of  sulphate  of  alu- 
mina, they  combine,  and  form  common  alum,  which  is  easily 
crystallized.  That  is  what  chemists  denominate  a  double  salt, 
being  composed  of  two  sulphates — the  sulphate  of  alumina 
and  the  sulphate  of  potash.  This  salt  has  been  known,  and  in 
general  use  among  dyers,  since  the  earliest  accounts  we  have 
of  their  processes;  but  the  true  nature  of  its  composition  was 
not  known  till  the  present  century.  The  alchemists  knew 
that  sulphuric  acid  was  one  of  its  constituents;  and  during  the 
last  century,  it  was  discovered  that  the  precipitate  which  falls 


3  Water. 

Chloride  of  aluminum. 


138 


ALUM. 


when  the  acid  is  neutralized  by  an  alkali,  is  a  particular  kind 
of  earth  which  chemists  called  alumina,  because  of  its  being 
obtained  from  alum.  Amongst  other  peculiar  properties  of 
alumina,  it  has  a  strong  attraction  for  organic  matter,  and 
withdraws  it  from  solutions  with  such  force,  that  if  the  purest 
water  be  not  used  when  preparing  it,  the  alumina  is  colored; 
and  when  digested  in  solutions  of  vegetable  coloring  matters, 
provided  the  alumina  be  in  sufficient  quantity,  it  will  carry 
down  all  the  coloring  matter  from  the  liquid.  By  this  means 
the  pigments  called  lakes  are  formed;  and  it  is  this  that  makes 
it  so  valuable  as  a  mordant.  The  fibre  of  cotton,  when  charged 
with  this  earth,  attracts  and  retains  coloring  matters. 

A  very  pure  alum  is  obtained  in  the  Eoman  States  from 
alum  stone,  a  mineral  which  is  continually  produced  at  the  Sol- 
fatara,  near  Naples,  and  other  volcanic  districts,  by  the  joint 
action  of  sulphurous  acid  and  oxygen  upon  some  of  the  feld- 
spathic  rocks.  This  mineral  contains  an  insoluble  subsulphate 
of  alumina,  with  sulphate  of  potash  ;  but  it  is  partially  decom- 
posed by  heat;  so  that,  for  the  preparation  of  alum,  the 
mineral  is  simply  heated,  till  sulphurous  acid  begins  to  escape, 
and  is  then  treated  with  water,  by  which  process  a  very  pure 
and  excellent  alum  is  procured — much  superior  to  that  manu- 
factured in  this  country.  The  alum  of  this  country  is  manu- 
factured from  a  mineral  termed  alum  shale,  a  kind  of  clay  slate, 
much  impregnated  with  sulphuret  of  iron,  which  is  essential  to 
the  manufacture.  The  general  composition  of  this  alum  ore,  as 
it  is  also  called,  is  as  follows,  observing  that  the  proportions  of 
the  several  components  vary  according  to  the  depth  from  which 
the  ore  is  obtained ;  the  table  is  therefore  to  be  considered  as 
giving  only  the  average  constitution  : — 


The  ore  is  built  up  in  large  heaps,  with  alternate  layers  of 
coal ;  these  heaps  are  set  on  fire,  and  allowed  to  burn  for  several 
weeks.  During  this  roasting  process,  a  portion  of  the  sulphur 
is  expelled,  but  the  greater  portion  of  it  is  converted  first  into 
sulphurous  acid,  by  taking  an  equivalent  of  oxygen  from  the 


Sulphuret  of  iron  .  . 
Oxide  of  iron   .    .  . 

Alumina  

Silica  

Lime  

Magnesia,  potash,  soda 
Coaly  matter    .    .  . 
Water  


26.5 
3.1 

18.3 

10.5 
3.0 
1.4 

28.7 
8.5 


100.0 


ALUM. 


139 


atmosphere,  and  finally  into  sulphuric  acid,  by  taking  a  farther 
proportion  from  the  peroxide  of  iron  contained  in  the  mineral. 
The  sulphuric  acid  does  not,  however,  remain  isolated,  but 
combines  with  the  iron  and  alumina,  and  forms  sulphates  with 
these  oxides.  The  roasting  being  completed,  the  material  of 
the  heap  is  removed  to  large  tanks  or  pits,  into  which  water  is 
allowed  to  flow,  and  which  dissolves  out  the  sulphates  formed 
in  the  process.  The  solution  is  run  into  large  tanks  and  evapo- 
rated, generally  by  causing  a  current  of  dry  heated  air  to  pass 
over  the  surface  of  the  liquid.  When  the  solution  is  in  this 
way  sufficiently  concentrated,  the  sulphate  of  iron  crystallizes, 
and  is  then  removed  ;  the  sulphate  of  alumina,  being  very  diffi- 
cult to  crystallize,  remains  in  solution.  All  the  iron  having  by 
this  means  been  separated,  the  sulphate  of  alumina  in  solution 
is  removed  to  other  vessels,  where  there  is  added  to  it  sulphate 
of  potash,  chloride  of  potassium,  or  other  salts  of  potash.  There 
is  then  formed  the  double  salt  of  potash  and  alumina,  which  is 
alum,  and  which,  after  a  few  days'  standing,  crystallizes,  and 
is  removed  and  packed  for  the  market.  There  are  some  modi- 
fications of  this  process  adopted  by  different  makers,  but  this 
description  exhibits  the  general  practice  of  the  manufacture, 
and  illustrates  sufficiently  the  principle  upon  which  the  prac- 
tice is  necessarily  based. 

Soda  may  be  used  in  the  operation  instead  of  potash,  which 
would  give  a  soda  alum,  but,  notwithstanding  its  being  cheaper, 
there  are  practical  objections  to  it.  Soda  alum  is  not  so  easily 
crystallized  as  common  alum,  and  it  effloresces  when  exposed 
to  the  air,  which  makes  it  take  the  appearance  of  a  dry  powder. 
Sulphate  of  ammonia  may  also  be  used  instead  of  potash, 
giving  an  ammonia  alum,  which,  however,  is  expensive,  and 
possesses  no  corresponding  advantage  over  the  ordinary  article.* 

The  following  analysis,  by  Dr.  Thomson,  of  the  alum  made 
in  this  country,  will  be  useful : — 

Potash  ....    9.86  1  G     ,  , 

Ai  ii  no  i  Symbols. 

Alumina  .       .  ii.ua  l  A1  03  3  S03  +  KO  S03  +  24  HO. 
Sulphuric  acid  .  32.85  f      *  3        3  3 
Water  ....  46.20  J 

100.00 

Thus,  every  100  lbs.  of  alum  contain  46  lbs.  of  water.  From 
the  nature  of  the  processes  by  which  the  alum  is  manufactured, 
we  may  expect  it  to  contain  small  traces  of  sulphate  of  iron,  a 
substance  very  deleterious  to  its  use  as  a  mordant  or  alterant. 

*  Most  of  the  alum  now  made  is  ammonia  alum. 


140 


ALUM. 


Iron  may  be  detected  by  dissolving  a  little  of  the  salt  in  dis- 
tilled water,  and  adding  a  few  drops  of  a  solution  of  red  prus- 
siate  of  potash ;  or  boiling  a  little,  with  the  addition  of  a  few 
drops  of  nitric  acid,  and  adding  yellow  prussiate  of  potash.  In 
both  cases,  a  deep  blue  color  is  immediately  produced,  if  iron 
is  present.  The  addition  to  a  solution  of  alum  of  a  few  drops 
of  gallic  acid  will  give  a  black  color,  if  iron  be  present.  Or, 
if  a  little  alum  be  put  into  a  vessel,  and  caustic  potash  added 
till  the  solution  is  strongly  alkaline,  then  the  whole  boiled,  and 
set  aside  to  cool  and  settle,  the  alumina  will  be  dissolved,  and, 
if  iron  be  present,  it  will  subside  to  the  bottom  as  a  brownish 
precipitate.  When  the  proportion  of  iron  is  considerable,  it  is 
better  to  reject  the  alum  altogether,  especially  for  bright  light 
shades.  We  have  often  experienced  bad  effects  from  the  use 
of  such  alum  upon  light  shades  of  drab  or  fawn  colors,  when 
dyeing  to  a  particular  pattern.  Having  obtained  the  particular 
shade,  on  adding  a  little  alum  as  raising,  the  iron,  by  combining 
with  the  sumach  upon  the  cloth,  produced  a  color  two  or  three 
shades  darker  than  required  ;  leaving  no  alternative  but  to  take 
off  the  color  and  dye  anew — a  process  much  more  difficult,  and 
'which  produces  a  color  much  less  brilliant  than  the  first. 

Pure  alum  is  soluble  in  water,  and  should  give  a  colorless 
solution. 

One  gallon  of  water  at  54°  Fahr.  dissolves  1  lb.  alum. 
One     "  "        86      "  "       2  " 

One     "  "      140      "  "       3  " 

One     "  "      158      "  "       9  " 

One     "  "      212      "  "     35  " 

Alum  forms  but  a  weak  mordant  for  cotton  goods,  owing  to 
the  strong  attraction  which  the'  sulphuric  acid  has  for  the  alu- 
mina; and  in  this  state  there  are  three  proportions  of  acid  to 
every  two  of  alumina.  But  if  we  neutralize  a  portion  of  the  acid, 
so  that  no  more  remains  than  is  necessary  to  hold  the  alumina 
in  solution,  which,  according  to  experiment  is  not  above  a  third 
of  the  acid  contained  in  common  alum,  its  properties  as  a  mor- 
dant are  greatly  improved.  That  the  amount  of  acid  admits 
of  being  reduced,  may  be  proved  by  taking  a  quantity  of  car- 
bonate of  soda,  sufficient  to  neutralize  the  whole  of  the  acid 
contained  in  a  given  portion  of  alum,  dividing  the  soda  solu- 
tion into  three  equal  portions,  and  adding  gradually  to  the 
aluminous  solution  (stirring  all  the  time)  two  of  these  portions  ; 
it  will  be  found  that,  although  the  alumina  is  at  first  precipi- 
tated, by  keeping  up  the  agitation  for  some  time,  the  precipitate 
again  dissolves,  forming  an  alum  containing  only  a  third  of  the 
acid  of  common  alum.    In  this  state,  alum  is  a  more  powerful 


ACETATE  OF  ALUMINA. 


141 


mordant  for  cotton,  as  the  base  is  held  more  feebly  by  the  sul- 
phuric acid,  and  is  readily  detached  by  the  superior  affinity  of 
the  cloth  to  form  a  mordant;  and,  thus  prepared,  it  is  perfectly 
pure;  any  iron  formerly  present  is  precipitated  in  the  process. 
Alum  in  this  state  is  known  by  the  name  of  cubical  or  basic 
alum,  from  the  form  in  which  it  crystallizes.  We  have  already 
referred  to  Eoman  alum  being  superior  to  other  alums.  For  a 
long  time,  the  dyers  considered  this  superiority  to  be  wholly 
owing  to  its  purity ;  but  a  chemical  investigation  shows  it  to 
be  caused  by  the  small  quantity  of  acid  it  contains  in  compari- 
son with  ordinary  alum. 

Sulphate  of  Alumina. — The  useful  principle  of  alum  is 
sulphate  of  alumina.  Several  attempts  have  been  made  to  in- 
troduce this  substance  in  the  practice  of  dyers,  which  have 
failed  on  account  of  the  sulphate  of  iron  remaining,  and  es- 
pecially in  consequence  of  a  large  excess  of  sulphuric  acid  in 
the  sulphate,  which  it  was  necessary  to  neutralize,  otherwise 
the  alumina  would  not  have  had  enough  affinity  for  the  fibre. 
At  the  present  day,  these  defects  have  been  overcome,  and  a 
neutral  sulphate  of  alumina  is  to  be  found  in  the  market,  which, 
for  a  given  weight,  contains  more  alumina  than  alum. 

Alum  Cake  is  kaolin  or  pure  clay  treated  by  sulphuric  acid, 
and  heated  until  dry.  It  is  a  mixture  of  silica  and  sulphate  of 
alumina. 

Aluminate  of  Soda. — This  substance,  which  begins  to  be 
used  as  a  mordant,  is  prepared  directly  from  the  mineral  kryo- 
lite,  which  is  deprived  of  its  fluorine  by  the  addition  of  lime ; 
or  from  another  mineral,  called  bauxite,  which  is  an  aluminate 
of  iron.  By  a  calcination  with  carbonate  of  soda,  the  iron  is 
eliminated,  and  the  aluminate  of  soda  is  lixiviated,  and  evapo- 
rated to  dryness. 

By  a  sufficient  quantity  of  hydrochloric  acid,  the  soda  is 
separated,  and  the  hydrated  alumina  which  is  left  is  soluble  in 
acetic  acid.  It  is  therefore  possible  by  this  means  to  make  a 
very  pure  acetate  of  alumina.  A  sample  of  commercial  alu- 
minate of  soda,  from  the  bauxite  contains: — 


Acetate  of  Alumina. — The  most  common  and,  we  believe, 
the  best  method  of  using  alumina  as  a  mordant,  is  by  substi- 
tuting acetic  acid  for  sulphuric  acid  as  its  solvent.  The  acetate 
of  alumina  has  several  advantages  over  the  sulphate :  1st,  the 


Soda  

Alumina  

Sulphate  of  soda  and  chloride  of  sodium  . 


43 
48 
9 


100 


142 


ACETATE  OF  ALUMINA. 


acetic  acid  is  not  so  hurtful  in  its  action  upon  the  vegetable 
coloring  matter;  2d,  it  holds  the  alumina  with  much  less  force 
than  sulphuric  acid,  and  consequently  yields  it  much  more 
freely  to  the  cloth ;  and,  3d,  being  volatile,  a  great  portion  of 
the  acid  flies  off  during  the  process  of  drying.  When  strong 
colors  are  wanted,  and  the  mordant  is  of  such  a  nature  as  will 
admit  of  being  dried,  it  is  better  to  dry  the  cloth  from  the 
mordant  previous  to  dyeing.  This  last  property  of  acetic  acid 
is  very  convenient,  as  it  frees  the  cloth  from  any  superfluous 
acid  which  may  have  been  in  the  mordant ;  besides,  it  has  been 
found  that,  during  the  drying  by  heat,  the  soluble  acetate  is 
converted  into  a  less  soluble  subacetate.  We  may  here  put  the 
dyer  in  mind,  that  when  goods  containing  volatile  acids  are 
drying,  no  other  goods  should  be  allowed  to  be  in  the  same 
apartment,  as  the  acid  will  be  absorbed  by  them,  and  will  affect 
almost  any  color  that  either  has  been  or  may  be  put  upon  them. 
Many  unpleasant  and  also  expensive  consequences  occur  from 
the  neglect  of  these  precautions. 

The  acetate  of  alumina  is  easily  prepared  by  mixing  a  solu- 
tion of  acetate  of  barytes,  lime,  or  lead  with  alum.  When  any 
of  these  salts  are  added  to  alum,  a  double  decomposition  takes 
place  ;  the  sulphuric  acid  of  the  alum  combines  with  the  base 
of  the  salt  which  falls  to  the  bottom,  and  the  acetic  acid  unites 
*  with  the  alumina,  forming  acetate  of  alumina,  which  remains 
in  solution  mixed  with  sulphate  of  potash,  which  formed  a 
constituent  of  the  alum.  The  acetate  of  lead  is  the  salt  ge- 
nerally used  for  this  purpose  in  the  dye-house;  the  proportions 
of  the  lead  and  alum  vary  according  to  the  nature  of  the  color 
to  be  dyed  and  the  peculiar  taste  of  the  dyer,  for  the  prepara- 
tion of  this  substance  is  one  of  those  operations  which  every 
one  who  practises  it  thinks  he  has  the  best  method,  but  so  far 
as  we  have  had  an  opportunity  of  knowing,  the  superiority  only 
existed  in  the  mind  of  the  individual,  or,  rather,  in  its  being 
kept  secret.  In  the  proportions  used  for  the  preparation  of 
this  mordant,  there  is  never  a  sufficient  quantity  of  acetate  of 
lead  to  precipitate  all  the  sulphuric  acid  in  the  alum.  This 
crystallized  acetate  of  lead  has  an  equivalent  of  190,  and  that 
of  alum  crystals  of  475  ;  but  the  alum  having  4  equivalents  of 
sulphuric  acid,  would  require  4  equivalents  of  acetic  acid  to 
take  its  place.    Thus  : — 


2  Al. 

3S04 


„Acetate  of  alumina. 


ACETATE  OF  ALUMINA. 


143 


So  that  the  equivalent  of  acetate  of  lead  190  must  be  multi- 
plied by  4,  giving  760,  to  be  equal  to  475  of  alum.  These  are 
far  from  the  proportions  used,  showing  that  the  mordant  is  not 
a  pure  acetate  of  alumina,  but  a  mixture  of  salts,  probably  of 
cubic  alum  with  acetate  of  alumina  and  sulphate  of  potash. 

The  following  method  we  have  generally  found  to  answer 
very  well :  Into  a  boiler  or  pot  put  20  lbs.  of  crystallized  alum 
with  about  nine  gallons  water,  and  boil  till  the  alum  is  com- 
pletely dissolved.  In  a  separate  vessel  dissolve  20  lbs.  of  ace- 
tate of  lead  in  about  three  gallons  of  boiling  water.  This  is 
added  to  the  alum  while  at  a  boiling  heat,  and  well  stirred. 
The  sulphuric  acid  combines  with  the  lead,  forming  an  insoluble 
sulphate  of  lead,  which  falls  to  the  bottom  as  a  heavy  white 
precipitate;  the  soluble  part  constitutes  the  mordant.  The 
difference  in  the  preparation  of  this  mordant  is  in  the  propor- 
tion of  lead  varying  from  one-half  of  the  alum  to  equal  weights. 
There  is  also  added  to  the  alum  and  lead  a  quantity  of  carbon- 
ate of  soda,  varying  from  four  to  eight  ounces  to  the  five  pounds 
of  alum.  This  is  added  for  the  purpose  of  neutralizing  a  por- 
tion of  the  acid  ;  but  there  are  many  dyers  who  will  not  use 
soda  or  any  other  alkaline  substance  when  light  bright  shades 
are  wanted,  under  the  impression  that  the  color  is  much  brighter 
without  alkalies ;  but  the  difference  of  hue  is  hardly  percepti- 
ble ;  some  use  lime ;  soda,  however,  is  best.  Without  soda  or 
some  other  alkaline  substance,  the  mordant  is  not  so  effective. 
There  are  also  some  who  object  to  the  use  of  soda,  as  it  throws 
down  the  alumina  ;  but  we  have  already  noticed  that  a  very 
little  acid  holds  the  alumina  in  solution ;  so  that  although  soda, 
when  added  to  the  acetate  of  alumina,  appears  to  precipitate 
the  alumina,  by  a  little  agitation  the  precipitate  is  again  dis- 
solved, forming  a  mordant  better  adapted  for  strength  of  color. 
From  the  following  recipes,  taken  from  a  French  work  on  dye- 
ing, it  will  be  observed  that  the  quantities  of  the  aluminous 
mordants  are  similar  both  in  England  and  France  : — 

60  gallons  boiling  water,  ^ 
100  pounds  of  alum,  !  This  mordant  is  best 

100  pounds  acetate  of  lead,        [       adapted  for  reds. 

10  pounds  crystallized  soda,  J 

80  gallons  boiling  water,  \ 
100  pounds  alum,  (  This  is  best  for  bright 

50  pounds  acetate  of  lead,        j  yellows. 

„    6  pounds  soda,  J 

In  addition  to  the  above,  Dr.  Ure,  in  his  Dictionary  of  the 
Arts  and  Manufactures,  article  "Calico-Printing,"  gives  another 
proportion : — 


144 


ACETATE  OF  ALUMINA. 


50  gallons  boiling  water. 
100  pounds  alum. 
75  pounds  acetate  of  lead. 
10  pounds  soda. 

The  following  curious  phenomenon  was  observed  by  Gay- 
Lussac,  viz.,  that  the  solution  of  a  pure  salt  of  the  acetate  of 
alumina  may  be  boiled  without  decomposition  ;  but  if  sulphate 
of  potash,  or  any  other  neutral  salt  of  an  alkali  be  present,  the 
solution  becomes  turbid  when  heated,  and  a  basic  salt  precipi- 
tates, which  dissolves  again  on  cooling.  Now  the  acetate  of 
alumina,  prepared  from  the  common  alum,  always  contains 
sulphate  of  potash.  If  by  the  presence  of  this  salt  a  portion 
of  the  acetate  of  alumina  be  thrown  down  when  hot,  and 
incorporated  with  the  sulphate  of  lead,  which  falls  in  a  very 
dense  state,  it  may  there  be  lost  to  the  dyer.  Whether  this 
be  so  we  know  not,  as  we  have  not,  since  we  knew  of  this 
phenomenon,  had  an  opportunity  of  putting  it  to  the  test ;  but 
it  would  be  advisable  to  stir  the  whole  after  becoming  cold, 
that  if  any  of  this  basic  salt  should  be  bound  up  with  the  pre- 
cipitate, it  might  be  set  at  liberty  and  dissolved;  but  it  must 
be  borne  in  mind,  that  if  this  be  stirred  when  cold,  it  takes  a 
long  time  to  settle. 

Nearly  all  the  acetate  of  alumina  used  in  dyeing,  is  pre- 
pared from  pyroligneous  acid,  and  is  called  by  calico-printers 
red  liquor,  but  by  dyers  mordant.  No  other  substance,  what- 
ever be  its  nature,  is  distinguished  as  a  mordant.  All  other 
mordants  have  their  technical  names.  The  pyroligneous  acid 
is  one  of  the  products  of  the  destructive  distillation  of  wood. 
The  hard  woods,  such  as  oak,  ash,  birch,  and  beech,  alone  are 
used  ;  they  are  put  into  large  cast-iron  cylinders,  so  constructed 
that  a  fire  plays  about  them  so  as  to  keep  them  at  a  red  heat, 
and  having  openings  through  which  all  volatile  matter  escapes 
by  pipes,  which  lead  into  condensing  vats.  The  products  thus 
obtained  consist  principally  of  pyroligneous  acid,  mixed  jkith 
a  black  tarry  matter,  having  a  very  strong  smell,  from  wfrlch 
the  acid  had  its  name,  although  it  has  been  long  since  known 
that  it  is  simply  acetic  acid  (vinegar).  There  is  a  great  variety 
of  other  substances  present,  some  of  which  have  very  singular 
properties,  and  some  of  the  continental  chemists  suppose,  they 
might  be  made  available  in  dyeing.  The  products  of  the  dis- 
tillation of  the  wood  are  allowed  to  stand  for  some  time,  aftpr 
which  as  much  of  the  tarry  matter  as  swims  is  skimmed  off; 
the  remainder  is  filtered,  after  which  it  is  put  into  a  boiler  and 
heated  a  little,  and  lime  added  by  degrees,  till  the  acid  is  neu- 
tralized ;  then  a  quantity  of  lime  is  added  in  excess,  and  the 


♦ 


ACETATE  OF  ALUMINA.  145 

whole  is  made  to  boil;  this  throws  up  the  tarry  matter  to  the 
top,  where  it  is  taken  off.  When  it  is  purified  as  much  as  it 
can  be  by  this  means,  it  is  siphoned  off  into  another  boiler, 
and  a  quantity  of  alum  is  added  ;  the  acetate  of  lime,  the  sul- 
phate of  alumina  and  potash,  mutually  decompose  each  other; 
the  sulphate  of  lime  falls  to  the  bottom,  and  the  acetate  of  alu- 
mina remains  in  solution,  which,  when  sent  to  the  dyers,  has 
sometimes  a  specific  gravity  of  1.90  (18  Twaddell),  although  it 
is  often  weaker,  ranging  from  12  to  18  Twaddell.  It  has  a 
dark-brown  color,  and  a  very  strong  pyromatic  odor.  When 
the  acetic  acid  is  wanted  pure,  it  passes  through  a  number  of 
other  .processes,  which  do  not  come  within  our  province  to 
describe  in  this  place. 

There  is  a  considerable  difference  in  the  quality  of  red  liquor, 
which  the  mere  specific  gravity  does  not  indicate,  as  this  can 
be  brought  up  by  the  addition  of  foreign  matters,  such  as  Bri- 
tish gum,  dextrine,  and  such  like.  A  very  simple  method  may 
be  adopted  to  test  the  effective  quality  of  the  mordant :  Take 
a  little  of  the  liquor,  and  evaporate  it  to  dryness,  then  burn  the 
residue  at  a  red  heat  until  white  in  color  ;  put  this  into  dis- 
tilled water,  which  will  dissolve  out  all  but  the  alumina. 
Another  way  is  by  digesting  a  little  of  the  red  liquor  in  nitric 
acid,  adding  ammonia  until  the  liquor  smells  of  it,  and  then,  by 
filtering,  the  alumina  is  obtained  upon  the  filter-paper.  We 
will  add  four  varieties  here,  to  show  the  variableness  in  quality 
of  the  liquor  as  supplied  to  the  dyer.  The  quantity  given 
refers  to  the  percentage  in  solution. 

■ci    v' i      j  v  1,10  m     jj    (  acState  of  alumina  .  .  15.8 

English  red  liquor — 14°  Twadd.  <     ,  t  .     «     .  ^ 

G  ^  (  sulphate  of  potash  .  .  8 


16.1 

q    .  i   tsj         -.o-io  m    aa         f  acetate  of  alumina  .  .  11.5 
Scotch,  No.  1 — 161°  Twadd.        <     ,  ,   .     „     '    ,  ' 
'  A  [  sulphate  oi  potash  .  .  2.6 


13.8 

acetate  of  alumina  .  .  14. 

1.2 


c    j.  i.  at    o    i  /( o  m     aa  (  acetate  of  alumina 

Scotch,  No.  2 — 14°  Twadd.         <     ,  ,   .     Q     .  , 
'  (  sulphate  or  potash 

l  ■ 


Scotch,  No.  3—15°  Twadd 


15.2 

acetate  of  alumina  .  .  12.2 
sulphate  of  potash  .  .  2.6 


14.8 


We  have  given  these  varieties  to  show  how  little  reliance 
ought  to  be  placed  on  the  indications  of  the  hydrometer.  No. 
10 


146 


ALUM  MORDANTS. 


3  is  of  a  higher  specific  gravity  than  the  English  red  liquor, 
but  far  inferior  as  a  mordant.  Again,  such  a  mordant  as  No. 
1  has  a  tendency  to  make  light  spots  upon  goods  dyed  green 
by  fustic  or  bark,  the  alumina  being  the  effective  agent  in  the 
red  liquor.  The  above  is  an  ample  illustration  of  the  necessity 
of  some  better  mode  of  testing  than  at  present  in  use. 

During  the  various  applications  of  these  aluminous  mordants, 
and  the  manipulations  attending  them,  many  curious  and  inter- 
esting chemical  phenomena  are  witnessed  by  the  dyer,  although 
his  familiarity  with  them  often  prevents  any  particular  remark  ; 
we  shall  instance  one  or  two  of  those  attendant  upon  the  pro- 
cess of  dyeing  madder  reds,  by  means  of  acetate  of  alumina. 
This  process,  however,  is  more  immediately  connected  with 
calico  printing,  while  our  particular  object  in  this  work  is  dye- 
ing yarns  and  cloth  to  be  finished  as  such.  The  cloth  to  be 
dyed  is  first  thoroughly  bleached  and  dried;  it  is  then  padded 
or  soaked  in  acetate  of  alumina,  about  the  specific  gravity  of 
40°  (8  Twaddell),  and  passed  at  full  breadth  through  nipping 
rollers  (squeezers).  These  are  large  rollers  covered  with  cloth, 
which  revolve  one  upon  another.  The  pressure  upon  the 
piece,  as  it  passes  through  for  the  purpose  we  are  describing, 
ought  to  be  such  that  it  will  dry  in  five  minutes,  passing  over 
rollers  in  a  stove  heated  to  160°  Fah.  Pieces  mordanted  with 
acetate  of  alumina,  and  dried  at  a  great  heat,  are  highly 
charged  with  electricity.  If  the  hand  be  suddenly  drawn  along 
the  piece,  a  complete  shower  of  fire  is  observed,  with  a  sharp 
crackling  noise,  at  the  same  time  a  prickling  sensation  is  felt. 
Whether  this  has  any  effect  upon  the  mordant,  in  its  imme- 
diately combining  with  other  substances,  we  do  not  know ;  but 
cloth  in  this  state  is  very  ill  to  moisten;  water  runs  off  it  as 
off*  a  duck's  wing,  but  as  yet  we  offer  no  explanation.  After 
being  dried,  the  goods  are  passed  through  a  dung  bath,  made 
up  with  about  one  part  cow's  dung  to  fifty  parts  water,  at  a  heat 
of  130°  Fahrenheit;  from  this,  they  are  well  washed  through 
the  dash-wheel.  Into  a  boiler  of  cold  water  is  put  from  one 
to  three  pounds  of  madder,  according  to  the  color  wanted,  for 
every  pound  of  cloth.  The  cloth  is  put  in,  and  a  fire  is  kindled 
under  the  boiler,  and  so  regulated  that  it  will  boil  in  two  hours, 
during  which  the  cloth  is  kept  running  over  a  winch,  or  wheel, 
first  in  one  direction  and  then  the  other,  and  kept  spread  as 
much  as  possible,  so  that  the  whole  surface  may  be  equally 
exposed  to  the  dyeing  operation.  The  boiler  is  kept  at  the 
boil  from  twenty  to  thirty  minutes;  this,  with  washing  first 
through  bran,  and  then  water,  completes  the  dyeing  operation. 
If  a  white  pattern  be  wanted  upon  these  reds,  the  pattern  is 
printed  upon  the  goods  with  citric  acid  (about  25°  of  Twaddell, 


ALUM  MORDANTS. 


147 


thickened  with  pipe-clay  and  gum),  about  twelve  or  twenty 
four  hours  after  being  dried  from  the  mordant.  This  decom- 
poses the  aluminous  mordant  upon  these  parts,  so  that  no  dye 
adheres  to  them  afterwards.  It  is  of  the  utmost  consequence 
that  the  goods  be  thoroughly  cooled  previous  to  printing  on  the 
resist,  otherwise  there  is  danger  of  its  not  being  successful. 

Now,  from  a  difference  in  the  manipulation,  or  a  little  varia- 
tion upon  some  of  these  processes,  several  curious  changes  take 
place  upon  the  mordant.  For  example,  were  the  pieces  merely 
washed  with  water  from  the  mordant,  previous  to  printing  on 
the  resist  acid,  although  the  treatment  be  every  way  else  the 
same,v  the  discharge  of  the  mordant  is  not  effected  ;  those  parts 
upon  which  the  citric  acid  is  printed  will  be  scarcely  observa- 
ble after  the  cloth  is  dyed,  while  in  the  other  case  they  are  per- 
fectly white. 

A  somewhat  similar  result,  in  reference  to  the  action  of  the 
discharge  acid,  takes  place,  if  the  heat  of  the  stove  in  which 
the  goods  are  dried  from  the  mordant  exceeds  a  certain  tem- 
perature, or  if  dried  upon  steam  rollers.*  No  acid,  printed 
upon  the  cloth  after  this,  will  produce  a  white,  except  it  be  of 
a  strength  that  will  destroy  the  fabric  of  the  goods ;  besides 
this,  the  colors  afterwards  dyed  upon  mordants  heated  in  this 
manner  are  extremely  bad,  being  heavy  and  dull. 

Various  opinions  have  been  offered  by  practical  men  upon 
the  probable  cause  of  these  changes.  Some  suppose  that,  by 
the  excess  of  heat,  the  acetate  of  alumina  is  altogether  decom- 
posed, the  acetic  acid  flying  off,  and  the  alumina  left  in  the 
goods  adhering  with  such  an  affinity  that  it  requires  a  stronger 
Hcid  than  the  cloth  will  bear  to  disengage  it;  but  from  the 
similarity  of  the  effects  which  take  place,  by  merely  washing 
the  piece  from  the  mordant,  this  opinion  is  liable  to  objection, 
lor  the  subacetate  of  alumina  is  not  decomposed  by  washing 
with  water;  however,  different  causes  may  produce  the  same 
effects.  If  this  opinion  be  correct,  the  circumstance  of  a  bad 
color  resulting  from  the  acetate  being  decomposed,  will  be  a 
proof  that  it  is  not  the  alumina  alone  which  constitutes  a  mor- 
dant, but  its  salt ;  in  this  case,  it  is  the  subacetate  of  alumina — 
the  acetic  acid  being  an  essential  ingredient  to  the  dyeing  pro- 
cess. This  we  are  inclined  to  believe,  for  in  those  mordants, 
as  we  have  already  stated,  where  the  acid  can  be  separated  by 
washing,  the  proper  color  is  not  produced  until  some  salt  or 
acid  be  added  to  the  coloring  matter  as  an  alterant.  It  is  sup- 
posed by  some  writers  that  the  dunging  and  washing  extract 

*  Large  metal  cylinders  into  which  steam  is  admitted,  and  the  cloth 
passed  over  the  surface. 


148 


SALTS  OF  ALUMINA. 


the  acid  from  the  mordant,  and  leave  the  base  upon  the  cloth. 
This  we  conceive  to  be  an  error  ;  for  although  the  part  which 
dung  acts  in  these  processes  is  not  well  understood,  yet  from 
the  analysis  of  this  substance,  and  the  nature  of  the  saltswhich 
are  supposed  to  be  useful  in  these  operations,  there  is  no  proba- 
bility of  the  aluminous  salt  being  decomposed.  One  principal 
use  of  the  dung  bath  is  to  combine  with  and  carry  off  any 
loose  or  supernatant  mordant  which  may  be  upon  the  cloth, 
not  combined,  and  which  might  affect  the  color,  or  more  par- 
ticularly the  parts  wanted  to  be  white. 

Alumina  combines  with  all  the  acids,  forming  salts  similar 
to  those  already  described,  and  all  difficult  to  crystallize,  ex- 
cept as  double  salts,  such  as  alum,  which  they  form  with  other 
salts  beside  those  named  ;  but  none  of  the  others  have  been 
introduced  into  the  dye-house. 

Alumina,  as  an  earth,  is  of  great  value  in  many  other  arts, 
as  in  pottery,  brickmaking,  &c.  It  also  forms  the  bases  of  some 
of  the  finest  precious  stones;  the  sapphire  and  ruby,  for  exam- 
ple, are  nearly  pure  alumina. 

The  salts  of  alumina,  such  as  alum,  act  towards  other  salts 
and  reagents,  as  under:  — 

Potash  White  precipitate,  which  is  redissolved 

in  an  excess  of  the  precipitant. 

Ammonia  ....  White  precipitate,  insoluble  in  an  ex- 
cess of  the  precipitant. 

Carbonate  of  potash  .    White  precipitate,  not  soluble  in  an 

excess  of  the  precipitant,  but  soluble 
in  caustic  potash. 

Caustic  soda  and  its  carbonate  act  in  the  same  way  as  caustic 
potash  and  its  carbonate. 

Carbonate  of  ammonia  and  phosphate  of  soda  act  in  the  same 
way  as  carbonate  of  potash. 

All  these  precipitates  are  soluble  in  acids. 

Oxalic  acid    ......  No  precipitate. 

Yellow  prussiate  of  potash  .  Precipitate,  after   standing  for 

some  time. 

Eed  prussiate  of  potash    .    .  No  precipitate. 

All  these  precipitates  of  alumina  have  a  bulky  and  a  kind  of 
plastic  appearance,  easily  recognized  and  distinguished. 

When  a  substance  containing  alumina  is  heated  to  redness, 
especially  before  the  blowpipe,  and  is  touched  with  a  solution 
of  nitrate  of  cobalt,  and  then  again  heated,  it  takes  a  beautiful 
blue  color.  In  this  way  a  very  small  portion  of  alumina  may 
be  detected  in  any  solid  substance;  but  when  the  substance 


MANGANESE. 


149 


is  in  solution,  it  must  be  detected  by  the  reaction  of  some  of 
the  reagents  given  above.  It  may  also  be  noticed,  that  when 
operating  to  obtain  a  precipitate,  it  is  necessary  to  be  careful 
that  only  pure  water  is  used  for  washing  the  precipitate.  If 
the  water  is  not  pure,  the  precipitate  will  attract  the  impurity, 
especially  if  it  consists  of  any  organic  matters,  and  thus  be- 
come tinged,  and  assume  an  appearance  as  if  iron  were  present. 


The  next  general  division  of  chemical  elements  consists  of 
the  Metals  Proper.  These  are  very  numerous,  but  a  great 
many  of  them  are  so  rare  as  to  have  been  seen  by  a  very  few 
chemists,  and  are  only  obtained  in  particular  localities;  con- 
sequently, their  properties  have  not  been  much  investigated, 
and  no  practical  applications  have  been  made  of  them.  Of  these, 
a  very  short  description  will  suffice,  so  that  our  remarks  may 
be  more  extended  upon  those  which  have  a  known  practical 
value.    The  first  of  which  is 


Manganese  (Mn  27.6). 

This  metal  is  not  found  in  nature  in  a  separate  state,  but 
exists  abundantly  in  combination  with  oxygen.  From  this  cir- 
cumstance it  was  long  considered  a  species  of  earth  like  mag- 
nesia, and  was  consequently  called  magnesia  nigra  ;  but  it  was 
discovered  to  be  the  oxide  of  a  metal  in  1774,  by  Scheele  and 
Gahn,  and  was  then  named  manganese. 

As  a  metal,  it  has  a  grayish-white  lustre,  resembling  cast- 
iron;  it  is  very  difficult  to  fuse,  and  it  combines  with  oxygen 
so  quickly  that  it  cannot  be  kept  in  the  open  air.  It  passes 
into  several  states  of  oxidation.  The  one  in  which  it  generally 
exists  in  nature  is  the  peroxide  having  2  proportions  of  oxygen 
to  1  of  metal  =  Mn  02.  When  this  oxide  is  heated  at  a  low 
red  heat,  it  loses  a  part  of  its  oxygen,  and  passes  into  the  state 
of  sesquioxide  =  Mn2  03.  When  heated  to  bright  redness,  it 
loses  more  oxygen,  and  becomes  what  is  termed  red  oxide,  or 
a  mixture  of  the  protoxide  Mn  0  and  of  the  sesquioxide  Mn2 
03.  The  peroxide  does  not  unite  with  either  acids  or  alkalies. 
When  boiled  with  sulphuric  acid,  one  proportion  of  the  oxygen 
is  evolved,  and  the  protoxide  Mn  0  unites  with  the  acid,  and 
forms  sulphate  of  manganese,  which  is  used  in  dyeing. 

Peroxide,  or  black  j°  Oxygen  gas. 

oxide  of  manganese 


Sulphuric  acid. 


Water. 

Sulphate  of  manganese. 


150 


MIXER  A  L  CAME  LEON. 


When  the  peroxide  is  digested  in  hydrochloric  acid,  chlo- 
rine is  evolved,  and  chloride  of  manganese  formed.  This  is 
often  done  in  houses  for  the  purpose  of  fumigation.  The  re- 
action is  thus  expressed  : — 


hydrochloric  acid 


[  CI..   Chlorine  gas. 

Two  proportions  of   j  CI.. 

H.. 
H.. 

0..  Water. 
Binoxide  of  manganese  •<  O  ..   y*  Water. 


(Mn   X  Chloride  of  manganese. 


The  oxide  of  manganese  is  extensively  used  in  the  manu- 
facture of  bleaching  powder,  for  obtaining  the  chlorine  from 
common  salt.   (See  page  79.) 

Manganese  combines  with  almost  all  the  acids  forming  salts, 
which  in  their  crystallized  or  dry  state  have  less  or  more  of  a 
pinky  hue.  In  making  these  salts  from  the  peroxide,  there  is 
always  oxygen  liberated  ;  they  are  therefore  all  what  are  termed 
salts  of  the  protoxide.  But  by  removing  the  acid,  the  protox- 
ide soon  combines  with  more  oxygen,  and  becomes  brown.  It 
is  this  circumstance  that  has  made  it  applicable  in  dyeing.  In 
preparing  any  of  the  salts  of  manganese  for  dyeing  purposes, 
care  should  be  taken  that  the  salt  be  free  from  iron,  as  that  metal 
is  deleterious.  The  sulphate  of  manganese  may  be  free  from 
iron  by  exposing  it  to  a  red  heat,  then  dissolving  the  residue 
in  water.  By  this  means  the  iron  present  is  peroxidized  ;  it  is 
thus  rendered  insoluble,  and  consequently  sinks  to  the  bottom. 

When  cotton  is  passed  through  a  solution  of  sulphate  of 
manganese,  and  then  through  a  weak  solution  of  an  alkali,  the 
manganese  oxide  is  left  within  the  fibre,  and  by  exposure  be- 
comes brown  by  attracting  more  oxygen.  Or  if  the  cloth  be 
immediately  passed  through  a  solution  of  weak  bleaching  liquor, 
the  protoxide  is  converted  into  peroxide  without  exposure. 
This  is  the  method  generally  adopted ;  it  gives  a  brown,  which 
is  very  dull  and  heavy,  but  also  very  permanent. 

Mineral  Cameleon. — When  peroxide  of  manganese  is  fused 
with  carbonate  or  caustic  potash,  there  is  formed  what  has  been 
long  known  as  the  mineral  cameleon.  When  this  is  first  put  into 
water,  it  produces  a  deep  green  solution,  but  passes  rapidly  to 
a  red  by  absorbing  oxygen.  This  compound  is  not  used  in 
dyeing,  but  we  think  it  contains  properties  worthy  of  exami- 
nation. It  illustrates  very  forcibly  the  effects  of  oxygen  in 
changing  the  colors  of  substances,  and  the  rapidity  with  which 
these  changes  take  place ;  accordingly  teaching  the  necessity  of 
attending  to  every  condition,  no  matter  how  apparently  trifling, 


IRON. 


151 


as  often  the  merest  trifle*  may  be  of  the  greatest  consequence 
in  a  process. 

The  salts  of  manganese,  in  solution,  are  affected  by  the  fol- 
lowing reagents. — 

Potash   Brown  precipitate. 

Soda  and  ammonia  Brown  precipitate. 

Carbonates  of  potash  and  soda    .  Brown  precipitate. 
Yellow  prussiate  of  potash    .    .  Dirty-green  precipitate. 
Eed  prussiate  of  potash     .    .    .  Brown  precipitate. 

Manganese  is  easily  detected  by  this  general  property  of 
turning  brown  when  exposed,  and  giving  a  brown  with  all  the 
alkaline  reagents. 

Iron  (Fe  28). 

This  is  one  of  the  most  useful,  generally  diffused,  and  abun- 
dant of  the  metals.  There  is  almost  no  substance,  whether 
organic  or  inorganic,  quite  free  from  iron.  Its  uses  in  the 
various  arts  and  purposes  of  life  are  innumerable.  The  most 
common  iron  ores  of  this  country  are  the  clay  iron-stones,  of 
which  there  are  several  varieties,  and  in  which  the  iron  exists 
as  a  carbonate  along  with  silica,  alumina,  carbon,  and  a  little 
sulphur.  The  ore  is  first  calcined  at  a  red  heat,  which  expels 
the  carbonic  acid  and  sulphur ;  it  is  then  mixed  up  with  lime- 
stone and  coal,  and  put  into  a  blast-furnace,  and  subjected  to 
intense  heat,  the  effect  of  which  is,  that  the  silica  and  alumina 
combine  with  the  lime,  and  form  a  glass  ;  the  coal  takes  the 
oxygen  from  the  iron,  and  passes  off  with  it  as  carbonic  acid  ; 
the  metal  meantime  fuses,  and  in  consequence  of  its  superior 
gravity,  sinks  to  the  bottom  of  the  furnace,  while  the  glass 
and  scorise  float  above  it,  and  are  run  off  separately  when  the 
furnace  is  tapped. 

Iron  combines  with  oxygen  in  two  proportions : — 

Protoxide  of  iron  Fe  O. 

Peroxide  of  iron      ...    .    .    .  Fe2  03. 

Both  of  these  oxides  unite  with  acids,  and  form  with  them 
two  classes  of  salts,  distinguished  from  each  other  by  affixing 
pro  and  per  to  their  names.  Both  salts  are  extensively  used 
in  the  dye-house. 

M.  Fremy  gives  the  following  statement  of  what  he  called  a 
third  oxide  of  iron,  which  he  had  obtained  in  combination  : — 

"This  oxide  is  obtained  by  igniting  a  mixture  of  potash  and 
peroxide  of  iron;  a  brown  mass  is  the  result,  which,  by  diges- 


152 


SULPHATE  OF  IRON. 


tion  in  water,  gives  a  beautiful  violet-red  colored  solution.  The 
compound  is  very  soluble  in  water.  A  large  quantity  of  water 
decomposes  it  in  course  of  time.  But  it  becomes  insoluble  in 
very  alkaline  water,  forming  a  brown  precipitate,  which  readily 
dissolves  in  pure  water,  and  affords  a  fine  purple-colored  solu- 
tion. A  temperature  of  212°  dissolves  it  immediately ;  all 
organic  substances  decompose  it;  and  hence  it  is  impossible  to 
filter  the  solution.  It  is  impossible  to  isolate  this  compound, 
for  when  the  red  solution  is  treated  by  an  acid,  as  soon  as  the 
potash  is  saturated,  oxygen  is  disengaged,  and  peroxide  of  iron 
precipitated.  If  the  acid  be  in  excess,  it  dissolves  the  peroxide, 
and  gives  rise  to  the  formation  of  a  persalt  of  iron.  It  is  stated 
to  possess  a  powerful  dyeing  principle." 

Protoxide  of  iron  is  very  difficult  to  be  obtained  in  an  iso- 
lated state,  on  account  of  its  great  affinity  for  oxygen,  which 
causes  it  to  pass  into  the  state  of  peroxide  very  rapidly.  When 
an  alkali  is  added  to  a  protosalt  of  iron,  the  protoxide  is  pre- 
cipitated as  a  hydrate  of  a  gray  color,  which,  by  exposure  to 
the  air,  soon  becomes  peroxide  of  an  ochrey-red  color,  as  is 
seen  almost  daily  in  the  dye-house  during  the  dyeing  of  nan- 
keen or  buffs  by  a  protosalt  of  iron  or  copperas. 

The  goods  are  dipped  into  the  sulphate  of  iron  solution,  and 
then  passed  through  lime-water;  the  lime  combines  with  the 
acid,  and  leaves  the  hydrated  protoxide  precipitated  within  or 
upon  the  fibre;  the  shade  is  then  greenish,  but  a  slight  expo- 
sure peroxidizes  the  iron,  and  produces  the  nankeen  or  buff. 
This  property  of  the  protoxide  of  iron,  of  passing  into  the  per- 
oxide by  its  strong  attraction  for  more  oxygen,  is  beautifully 
applied  in  some  of  the  operations  of  dyeing  besides  the  one 
referred  to,  and  which  will  be  more  fully  described  when  treat- 
ing of  the  blue  vat. 

Sulphate  of  Iron  {green  vitriol,  or  copperas). — This  salt  is 
very  easily  prepared,  merely  by  adding  metallic  iron  to  sul- 
phuric acid,  which  has  been  diluted  by  3  or  4  parts  of  water. 
The  iron  quickly  dissolves,  with  rapid  evolution  of  hydrogen 
gas.    The  reaction  taking  place  may  be  thus  represented : — 


When  as  much  iron  is  dissolved  as  the  acid  will  take,  the  solu- 
tion is  evaporated  by  heat,  until  a  pellicle  or  thin  skin  appears 
on  the  surface.  It  is  then  set  aside  in  a  cool  place,  and  in  a 
short  time  there  is  formed  a  quantity  of  green-colored  crystals 
of  sulphate  of  iron.  These  crystals  contain  7  proportions  of 
water  of  crystallization,  or  in  iOO  parts 


Sulphuric  acL 
Iron  


Fe.. 


Sulphate  of  iron. 


Hydrogen  gas. 


SULPHATE  OF  IRON". 


153 


Sulphate  of  iron,  Fe  S04    54.5 

Water  45.5 


100.0 

If  these  crystals  are  heated  a  little  above  the  boiling  point 
of  water  to  238°  Fah.,  they  part  with  all  this  water  except  one 
proportion,  or  about  10  per  cent.  The  salt  also  loses  its  green 
color,  and  becomes  white.  The  crystals  of  sulphate  of  iron 
require  the  following  quantities  of  water  to  dissolve  them: — 


1 

gallon  water  at 

50° 

Fah.  dissol 

ves   6  lbs. 

cr 

1 

•  (i 

59° 

ci 

7 

t< 

1 

it 

75° 

a 

HI 

u 

1 

ii 

109° 

a 

15 

u 

1 

a 

115° 

tt 

22f 

u 

1 

it 

140° 

a 

261 

a 

1 

ii 

183° 

u 

27 

a 

1 

ti 

194° 

tt 

37 

a 

1 

ci 

212° 

tc 

33| 

This  table,  which  is  of  a  similar  character  to  tables  of  many 
other  substances  dissolving  at  a  certain  temperature,  is  inte- 
resting, and  accounts  for  many  of  the  circumstances  occasion- 
ally observed  in  the  dye-house — that  sometimes  the  same  stuff 
seems  much  more  difficult  to  dissolve  than  at  other  times.  Tt 
also  shows  why  crystallization  may  occur  much  more  rapidly 
at  one  time  than  at  another.  If  we  note  the  increase  of  heat 
and  solubility,  we  shall  see  how  irregular  they  are: — 


1st,  an  increase  of 

9° 

dissolves  1  lb. 

more  than  at 

50° 

2 

16° 

"  41 

ii 

59° 

3 

34° 

"  H 

tt 

75° 

4  « 

6° 

"  7| 

a 

109° 

5  " 

25° 

"  3J 

t< 

115° 

6  " 

43° 

"  0| 

u 

140° 

7 

11° 

"  10 

ii 

183° 

8  « 

18° 

"  34 

less  than 

194° 

Ten  gallons  water,  at  194°,  will  dissolve  100  lbs.  more  cop- 
peras than  the  same  quantity  of  water  only  11°  colder;  a  fact 
quite  sufficient  to  account  for  many  of  the  phenomena  which 
exist  in  the  practical  operations  of  the  dye-house. 
.  The  sulphate  of  iron  of  commerce  is  not  made  by  dissolving 
metallic  iron  in  acid,  which  would  be  too  expensive  a  process, 
but  from  the  sulphureted  ores  of  iron  (iron  pyrites).* 

*  Large  quantities  of  copperas  are  produced  by  dissolving  scrap  iron  in 
refuse  sulphuric  acid  from  alum,  petroleum,  and  oil  works. 


154 


SULPHATE  OF  IRON. 


We  have  already,  in  treating  of  alum,  given  an  account  of 
the  manufacture  of  a  great  quantity  of  the  copperas  of  com- 
merce; but  there  are  numerous  and  extensive  places  for  manu- 
facturing this  salt  alone,  where  no  alum  is  made.  The  opera- 
tions are,  however,  nearly  the  same  as  those  described  for 
alum. 

Iron  pyrites  is  a  bisulphuret  of  iron,  Fe  S2;  in  100  parts  it 
has  52  of  sulphur  and  48  of  iron.  This  compound,  when 
obtained  from  the  older  geological  formations,  undergoes  spon- 
taneous decomposition  by  exposure  to  the  air  and  moisture ; 
the  sulphur  combines  with  the  oxygen  of  the  air,  and  forms 
sulphurous  acid,  which  again,  in  the  presence  of  water  and 
oxide  of  iron,  takes  more  oxygen,  and  becomes  sulphuric  acid, 
which  in  turn  combines  with  the  iron.  Generally,  these  pyrites 
are  made  into  large  heaps  and  set  on  fire,  in  the  same  manner 
as  the  alum-shale  is  treated  in  the  preparatory  process  of  the 
alum  manufacture.  This  roasting  causes  the  rapid  oxidation 
of  the  sulphur,  and  consequent  formation  of  the  sulphate  of 
iron,  which  is  all  dissolved  out,  by  passing  water  through  the 
heaps  and  collecting  it  into  tanks.  Owing  to  the  excess  of 
sulphur  over  the  iron,  there  is  generally  in  the  solution  an  ex- 
cess of  acid,  with,  also,  some  persalt  of  iron,  and  often  small 
quantities  of  copper,  which  would  be  deleterious.  To  get  rid 
of  this,  a  quantity  of  old  iron  is  put  into  the  solution,  which 
takes  up  the  excess  of  acid  at  the  same  time  that  it  precipitates 
the  copper  from  the  solution.  Thus, 

Old  iron   Fe  Sulphate  of  iron. 


It  reduces  all  the  persulphate  of  iron  to  the  state  of  protosul- 
phate:  Thus, 


The  solution  is  then  evaporated  to  a  proper  density  and  crys- 
tallized. This  method  of  adding  old  iron  to  produce  the 
changes  described,  not  being  in  all  cases  adopted,  gives  rise  to 
some  of  the  varieties  of  copperas  found  in  the  markets,  concern- 
ing which  there  is  much  prejudice  in  the  minds  of  dyers. 

M.  Dumas  ascribes  the  variations  to  the  formation  of  a 
double  salt  of  the  proto  and  per  sulphate,  during  the  decompo- 
sition of  the  pyrites.    M.  BansdorfF  [Records  of  General  Science) 


Sulphate  of  copper 


Persulphate  of  iron  {  S04 


Old  iron 


SULPHATE  OF  1KOX. 


155 


states,  that  there  are  three  varieties  of  the  protosulphate  of  iron  ; 
the  first  greenish-blue,  formed  from  an  acid  solution  free  from 
peroxide;  the  second,  dirty-green,  from  a  neutral  solution  with- 
out peroxide;  and  the  last,  emerald-green,  from  a  solution  im- 
pregnated with  peroxide  salt.  This  we  know  is  consistent 
with  experience — that  answering  the  description  of  his  second 
variety  being  the  best  for  general  use  ;  but  the  selection  of  this 
particular  quality  of  copperas  has  led  dyers  into  a  fatal  preju- 
dice. Sulphate  of  iron  crystallized  from  a  neutral  solution,  if 
kept  any  time,  assumes  a  rusty  appearance  by  absorbing  oxygen, 
and  forming  a  film  of  peroxide  of  iron.  Now,  good  copperas 
having  generally  this  appearance,  especially  on  the  surface  of 
the  cask  wrhen  opened,  dyers  pretty  generally  entertain  the 
opinion  that  it  is  to  this  redness  it  owes  its  superior  quality. 
This,  we  need  hardly  say,  is  an  erroneous  opinion,  concerning 
which,  Mr.  Parks  mentions,  in  his  Chemical  Essays,  that  some 
unprincipled  dealers  take  the  advantage  to  sprinkle  lime  on  the 
top  of  the  cask  to  peroxidize  the  surface,  and  make  the  dyers 
believe  that  they  have  got  a  lot  of  excellent  old  copperas. 

As  copperas  is  generally  judged  of  by  the  color,  the  worst 
colored  copperas  has  sometimes  a  solution  of  common  salt  or 
of  lime  sprinkled  upon  it  to  give  it  a  dark  tint;  but  although 
this  may  deceive  the  eye,  it  does  not  improve  its  bad  qualities. 

Copperas,  crystallized  from  solutions  of  sulphate  of  alumina, 
will  also  have  an  acid  reaction  when  used  for  some  of  the  pur- 
poses of  the  dye-house,  such  as  the  blue  vat,  and  may  be  the 
origin  of  the  light-green  colored  copperas,  by  giving  much  more 
water  of  crystallization  than  the  other.  The  difference  of  value 
between  the  light  green  watery-colored  crystal  and  the  dark- 
green,  is,  by  experience,  about  14  per  cent,  in  favor  of  the  latter. 
The  effects  of  this  will  be  noticed  more  fully  under  the  blue  vat. 
But  these  results  we  believe  to  be  the  reason  why  a  practical 
dyer,  in  an  excellent  treatise  upon  his  trade,  states  that  there  is 
a  bisulphate  of  iron,  and  warns  the  trade  against  its  use.* 

As  this  watery-looking  bluish-green  copperas,  according  to 
Bansdorff,  crystallizes  from  an  acid  solution,  it  is  probable  that 
the  extra  proportion  of  acid  which  is  found  in  it,  is  owing  to  a 
portion  of  mother-liquor  being  mechanically  combined  with 
the  crystals,  but  not  forming  an  essential  ingredient  in  the  com- 
position of  the  salt.  And  if  the  salt  has  been  crystallized  from 
sulphate  of  alumina,  the  excess  of  acid  will  be  more  apparent. 

The  result  of  experience  upon  the  relative  value  of  the  light- 
green  watery-colored  copperas  over  the  dark-green,  or  what  are 
generally  termed  new  and  old,  is  as  21  to  24,  or  100  lbs.  of  best 

*  Cooper's  Treatise  on  Practical  Dyeing. 


156 


SULPHATE  OF  IRON. 


old  copperas  is  worth  114  lbs.  of  new  light-green.  In  testing, 
there  is  always  an  excess  of  acid,  but  not  in  quantity  anything 
like  this  difference.  As  the  color  of  the  crystals  of  sulphate  of 
iron  depends  upon  the  presence  of  water,  may  it  not  therefore 
be  inferred  that  the  difference  of  color  depends  upon  the  pro- 
portion of  water  present  in  the  crystals,  which,  if  this  be  the 
case,  will  account  for  the  different  proportions  of  iron  which  we 
have  often  found  in  the  same  weight  of  the  salt.  It  has  been 
already  noticed,  that  of  the  seven  proportions  of  water  which 
copperas  contains,  it  loses  six  at  238°.  We  took  20  grains  of 
each  of  the  good  and  bad  qualities  of  copperas,  reduced  them  to 
coarse  powder,  and  submitted  them  to  a  heat  of  between  305° 
to  400°,  and  taking  the  mean  of  several  experiments,  the  bad 
copperas  lost  1J  grains  more  than  the  other,  or  1\  per  cent., 
a  result  which  agrees  with  the  experience  of  the  dyer.  It  being 
well  known  that  copperas,  being  exposed  to  the  air  in  a  dry 
place,  loses  water. 

English  copperas  is  considered  superior  to  Scotch.  The 
former  is  mostly  made  from  pyrites,  while  the  latter  is  made 
from  alum  shale,  and  is  therefore  very  liable  to  contain  small 
portions  of  sulphate  of  alumina;  and,  being  crystallized  from  a 
strong  solution  of  the  sulphate  of  a  salt  of  another  metal,  has 
every  chance  of  being  inferior. 

The  presence  of  alumina  may  be  detected  by  dissolving 
some  of  the  salt  in  water,  and  boiling  the  solution,  during 
which  a  few  drops  of  nitric  acid  are  added  to  peroxidize  the 
iron,  which  is  known  by  the  solution  becoming  a  clear  amber 
color.  Caustic  potash  is  then  added  in  considerable  excess, 
until  the  solution  is  alkaline,  and  the  whole  is  then  boiled 
for  some  time  and  passed  through  a  filter  upon  which  the 
peroxide  of  iron  is  retained.  The  solution  contains  the  alumina. 
The  potash  is  neutralized  by  sulphuric  acid,  and  on  adding 
ammonia  to  this  solution,  if  alumina  be  present,  a  flocculent 
white  precipitate  is  obtained.  Other  tests  for  alumina  are 
given  under  that  element.  If  ammonia  be  added  to  the  iron 
precipitate  retained  upon  the  filter,  the  solution  passing 
through  will  become  blue,  if  copper  be  present.  It  is  best  to 
test  for  the  presence  of  copper  separately ;  this  is  done  by 
dissolving  the  copperas,  as  described,  peroxidizing  with  acid, 
adding  ammonia  instead  of  potash,  and  filtering;  the  slightest 
trace  of  copper  will  tinge  the  solution  blue.  Or  it  may  be 
detected  by  dissolving  a  little  of  the  crystals,  and  putting 
into  the  solution  a  piece  of  clean  polished  iron,  such  as  the 
blade  of  a  knife;  when,  if  any  copper  be  present,  it  will  be 
precipitated  upon  the  iron  in  a  metallic  state.  The  presence 
of  zinc  may  be  detected  in  copperas  by  taking  the  ammoniacal 


ACETATE  OF  IRON. 


157 


solution  which  has  passed  through  the  iron  in  testing  for 
copper,  and,  if  no  copper  be  present,  pass  a  stream  of  the  sul- 
phuretted hydrogen  gas  through  the  solution  ;  the  zinc,  if  there 
be  any  present,  will  give  a  white  precipitate.  This  metal  is, 
however,  very  seldom  found  in  copperas.  The  effects  of  the 
presence  of  these  salts,  in  some  of  the  operations  where  cop- 
peras is  used,  will  be  considered  when  treating  of  the  blue  vat. 
Magnesia  is  occasionally  found  in  copperas,  but  its  reactions 
are  not  deleterious. 

Chloride  of  Iron. — Iron  is  easily  dissolved  in  hydrochloric 
acid  when  treated  in  the  same  way  as  was  described  for  dis- 
solving the  metal  in  sulphuric  acid,  and  the  product  is  chloride 
of  iron. 

Hydrochloric  acid    |  j^jj  ^  drogen  gas. 

Iron  Fe^  -  Chloride  of  iron. 

This  salt  crystallizes  in  green-colored  crystals,  but  with  diffi- 
culty. The  crystals  are  very  soluble  in  water,  and  pass  rapidly 
into  the  perstate.  For  some  purposes  in  dyeing,  this  salt  could 
be  used  equally  with  copperas,  but  for  others,  such  as  the  blue 
vat,  it  would  not  do  so  well.  Moreover,  the  expense  of  making 
it  precludes  its  extensive  use  in  the  arts. 

Carbonate  of  Iron. — This  salt,  as  we  have  already  said, 
exists  as  an  ore ;  but  it  is  easily  prepared,  by  adding  to  a  solu- 
tion of  copperas,  a  solution  of  carbonate  of  potash  or  soda.  It 
is  a  whitish  green  colored  precipitate,  and  is  obtained  by 
double  decomposition. 

Carbonate  of  potash    |g-  ^\mLIT^ 

Sulphate  of  iron  .  .    \  ^  4  ~  ,      ,     *  . 

1  (Fe..  -^-Carbonate  of  iron 

(precipitate). 

This  precipitate  cannot  be  dried  in  the  air  without  losing  its 
carbonic  acid,  and  passing  into  the  state  of  peroxide;  but  it 
is  soluble  in  water  impregnated  with  carbonic  acid.  This  is 
the  state  in  which  iron  is  generally  held  in  solution  in  spring 
waters. 

Acetate  of  Iron. — Acetic  acid,  or  vinegar,  acts  readily 
upon  iron,  dissolving  it,  and  forming  the  acetate,  which  crys- 
tallizes in  small  green  crystals,  very  rapidly  acted  upon  by  the 
air.  This  salt  is  much  used  in  dyeing  in  the  liquid  state;  it 
is  known  as  iron  liquor,  and  pyrolignite  of  iron,  from  its  being 
prepared  on  the  large  scale  with  crude  wood  vinegar.  The 
acetate  of  iron  may  be  prepared  by  mixing  together  acetate  of 
lead  and  protosulphate  of  iron.    The  sulphate  of  lead  is  formed 


158 


NITRATE  OF  IRON. 


and  falls  to  the  bottom  ;  the  acetate  of  iron  remains  in  solu- 
tion. The  pyrolignite  of  iron  is  in  general  preferable.  It  is 
prepared  by  allowing  iron  to  steep  in  pyroligneous  acid  (im- 
pure acetic  acid)  for  several  weeks.  As  this  acid  contains  a 
quantity  of  pyrogenous  oils  and  other  impurities,  it  preserves 
the  iron  for  a  longer  time  in  a  state  of  protoxide  than  almost 
any  other  solvent  available  in  the  arts;  hence  the  decided 
preference  given  to  it  by  practical  men.  We  shall  often  have 
occasion  to  refer  to  this  subject,  as  it  is  one  which  is  too  much 
neglected,  and  which  produces  many  serious  evils.  It  may, 
however,  be  in  the  meantime  observed,  that  pyrolignite  of 
iron,  used  instead  of  copperas  in  dyeing  black,  gives  a  prefer- 
able shade  of  color. 

The  value  of  this  solution  may  be  taken  by  evaporating  a 
known  weight  to  dryness,  and  burning  the  residue  until  all 
organic  matters  are  consumed,  when  there  remains  only  the 
iron  as  a  peroxide  :  every  forty  grains  of  the  peroxide  will  be 
equal  to  ninety-six  of  the  acetate  of  iron  in  the  solution.  The 
operation  is  very  simple,  and  the  percentage  of  acetate  of  iron 
in  the  solution  known.  The  average  of  good  iron  liquor  ranges 
about  13.5  per  cent,  of  pure  protoacetate  of  iron,  the  specific 
gravity  being  about  1.085  =  17°  Twaddell.  The  state  of 
oxidation  in  which  a  metal  exists,  when  used  as  a  mordant, 
ought  to  be  strictly  attended  to. 

Iron  combines  in  the  protostate  with  oxalic  acid,  tartaric 
acid,  and,  indeed,  with  all  the  acids,  but  these  salts  possess  no 
peculiar  advantages  over  those  before  described  to  warrant  any 
extra  expense  in  preparing  them. 

Persulphate  of  Iron. — Persalts  of  iron  are  also  exten- 
sively used  in  the  dye-house.  The  persulphate  of  iron  may 
be  easily  prepared  by  boiling  a  solution  of  copperas,  to  which 
a  few  drops  of  sulphuric  acid  have  been  added,  and,  while 
boiling,  adding  a  very  small  portion  of  nitric  acid,  or  any  ni- 
trate ;  red  fumes  are  given  off,  and  the  solution  becomes  of  a 
beautiful  amber  color.  It  is  then  in  the  state  of  a  persalt. 
Chlorate  of  potash  may  be  used  instead  of  nitric  acid  or  nitrates. 
The  persulphate  of  iron  might  be  advantageously  used  for 
many  operations,  and  be  cheaper  than  the  nitrate  of  iron. 

Nitrate  of  Iron. — This  is  the  persalt  of  iron  generally 
used  in  the  dye-house.  It  is  made  by  putting  clean  iron  into 
nitric  acid,  by  which  it  is  very  quickly  dissolved.  The  iron 
ought  to  be  added  as  long  as  the  acid  continues  to  dissolve  it; 
but  cautiously,  otherwise  the  action  will  be  so  violent  as  to 
cause  it  to  boil  over.  When  engaged  in  this  process,  care 
ought  to  be  taken  not  to  breathe  any  of  the  fumes  which  come 
off,  as  they  are  very  destructive  to  health.    The. reaction  which 


NITRATE  OF  IRON. 


159 


takes  place  between  the  acid  and  the  iron  may  be  expressed 
as  in  the  table  below — which  we  introduce  by  remarking  that, 
in  dissolving  iron  in  sulphuric  or  hydrochloric  acid,  there  is 
merely  a  substitution  of  the  iron  for  the  hydrogen  (see  p.  45); 
but  with  nitric  acid  a  different  range  of  affinities  takes  place: 
the  elements  of  the  acid  are  not  held  together  so  powerfully  as 
those  of  sulphuric  acid  ;  so  that  one  proportion  of  the  nitric 
acid  is  broken  up,  producing  the  following  arrangement: — 


The  binoxide  of  nitrogen  is  the  gas  passing  off;  but  it  in- 
stantly combines  with  more  oxygen,  and  forms  peroxide  of 
nitrogen. 

The  nitrate  of  iron  alone  dyes  a  buff  or  nankeen  color, 
which  is  probably  the  easiest  dyed  of  any  of  the  colors,  and  is, 
at  the  same  time,  very  permanent.  The  process  only  requires 
that  a  little  of  this  salt  be  put  into  water,  and  that  the  goods 
be  immersed  in  the  solution  for  a  few  minutes,  then  washed  in 
clean  water  and  dried.  Passing  them  through  a  weak  soap 
solution  softens  the  goods,  and  gives  clearness  to  the  tint. 
But  the  particular  use  of  this  salt  is  for  Prussian  blue.  The 
goods  are  first  dyed  buff'  by  the  salt  of  iron,  then  thoroughly 
washed  and  put  into  a  very  dilute  solution  of  ferroprussiate  of 
potash,  made  acid  by  a  few  drops  of  sulphuric  acid  ;  they  are 
washed  from  this  in  clean  water,  to  which  a  little  alum  has 
been  added.  (This  is  only  for  light  blues  on  cloth  ;  but  for 
dark  blues,  and  for  yarn,  the  proper  methods  will  be  given 
hereafter.)  We  have  known  many  attempts  made  to  substitute 
copperas  for  nitrate  of  iron  in  dyeing  Prussian  blue,  but  need 
hardly  say  they  were  unsuccessful.  A  very  little  knowledge 
of  the  nature  of  these  salts  would  have  told  the  experimenters 
that  protosalts  of  iron  give  only  a  grayish  color  with  yellow 
prussiate  of  potash;  but,  with  red  prussiate  of  potash,  copperas 
is  a  better  mordant  than  nitrate  of  iron,  as  the  red  prussiate 
gives  a  dark  blue  with  the  protosalts,  and  only  a  greenish 
gray  with  the  persalts  of  iron. 


N.. 
O.. 


Binoxide  of  nitrogen. 


One  nitric  acid 


Three  proportions 

nitric  acid  

Two  proportions  of  iron 


160 


NITRATE  OF  IRON. 


The  preparation  of  nitrate  of  iron  (killing  iron)  is  apparently- 
one  of  the  most  simple  operations  of  the  dye-house,  as  all  that 
is  required  is  to  place  metallic  iron  into  nitric  acid;  but  the 
practical  dyer  often  experiences  difficulties  which  he  cannot 
account  for,  and  which  alter  materially  his  shades  and  colors. 
Sometimes,  as  we  have  already  noticed,  the  iron  seems  not  to  be 
acted  upon;  at  another  time  the  action  is  so  rapid  that  there 
is  a  difficulty  in  preventing  the  liquid  boiling  over.  When 
the  acid  is  a  little  diluted,  and  the  iron  is  added  in  small  pieces, 
the  action  is  violent,  and  there  is  formed  a  brown  turbid 
clay-looking  solution.  Colors  dyed  by  the  iron  in  this  state 
are  never  brilliant.  We  have  seen  solutions  of  this  sort  di- 
luted largely  with  water,  the  brown  mass  allowed  to  settle, 
and  the  clear  only  used,  but  this  is  tedious,  and  not  good  after 
all.  The  best  means  of  improving  this  mordant  is  to  remove 
all  metallic  iron,  add  a  little  nitric  acid,  and  apply  heat. 

When  the  nitric  acid  is  not  diluted,  and  the  iron  dissolves 
freely,  and  when  the  acid  is  saturated  with  iron,  if  the  remain- 
ing metallic  iron  is  not  removed,  it  continues  to  dissolve  by 
the  reaction  of  the  nitrate  of  iron  upon  it  thus: — 


Protonitrate. 
^Protonitrate. 


One  part  nitrate  of  iron 


One  part  iron  ....     Fe  Protonitrate. 


This  protonitrate  rapidly  imbibes  oxygen,  passes  into  the  per- 
nitrate,  and,  in  so  doing,  liberates  a  portion  of  oxide  of  iron, 
which  collects  at  the  bottom  of  the  vessel,  and  accumulates  so 
rapidly  that  the  iron  solution  is  soon  converted  into  a  brown 
paste.  This  can  be  avoided  by  taking  out  the  iron  when  the 
acid  is  saturated,  and  before  this  deposit  begins.  The  addition 
of  a  little  acid  and  heat  redissolves  this  oxide;  or  a  little  sulphu- 
ric or  hydrochloric  acid  also  dissolves  it,  and  with  it  forms  an 
excellent  mordant. 

A  still  more  remarkable  circumstance  often  occurs:  the  iron 
being  placed  in  the  acid,  and  action  going  on  favorably,  after 
a  few  hours,  particularly  if  the  weather  be  cold,  the  solution  is 
observed  to  have  a  greenish-yellow  color,  and  the  vessel  is 
found  to  be  half  filled  with  crystals  of  a  light  yellow  tint. 
Although  these  crystals  when  dissolved  in  water,  or  the  solu- 
tion above  the  crystals,  may  be  used  for  dyeing,  they  give 
varieties  of  quality  from  the  usual  iron  solution,  which  often 
seriously  destroy  the  method  of  the  dye-house.  The  true 
nature  of  the  crystals  is  not  well  understood,  and  it  is  difficult 


PROTOSALTS.  .  ,  161 

to  get  at  their  examination,  as  they  are  very  deliquescent,  dis- 
solve easily  in  water,  and  even  in  their  own  water  of  crystal- 
lization, by  a  slight  elevation  of  temperature  above  summer 
heat.  When  put  upon  blotting-paper  they  are  decomposed, 
and  the  paper  imbibes  much  of  the  iron.  We  long  thought 
that  they  were  caused  by  the  formation  of  ammonia  in  dissolv- 
ing the  iron,  but  experiments  have  failed  to  show  the  slightest 
trace  of  ammonia.  The  analysis  of  these  crystals,  by  J.  M. 
Ordway,  gave  3  nitric  acid,  1  peroxide  iron,  and  18  water  =3 
N05  +  Fe2  03+  18  HO.  The  same  author  has  examined  nitrates 
of  iron  of  different  qualities,  and  states  that  nitric  acid  combines 
definitely  with  various  proportions  of  peroxide  of  iron  and 
water,  forming  what  he  terms  basic  nitrates,  varying  from  3 
acid,  and  1  peroxide  iron,  to  3  acid,  and  2,  3,  6,  8,  12, 15, 18,  and 
24  peroxide  of  iron,  wTith  various  definite  quantities  of  water, 
giving  an  interest  to  this  salt  of  the  highest  sort,  and  amply 
accounting  for  the  great  difference  experienced  in  its  use  for 
dyeing ;  and  also  for  the  ease  with  which  peroxide  of  iron  is 
fixed  upon  the  fabric  when  put  into  this  salt ;  the  basic  salt 
being  decomposed,  and  a  portion  of  the  oxide  of  iron  left  upon 
or  within  the  fibre.  There  are  many  other  phenomena  ob- 
served in  working  with  these  salts,  which  we  shall  yet  have 
occasion  to  notice. 

Any  other  persalt  of  iron  may  be  formed  by  adding  ammo- 
nia, soda,  or  potash  to  the  nitrate  of  iron  solution,  so  long  as  a 
precipitate  is  formed,  washing  the  precipitate,  by  repeatedly 
filling  the  vessel  which  contains  it  with  water,  allowing  it  to 
settle,  and  decanting  off  the  clear,  then  adding  to  the  precipi- 
tate the  acid  of  which  the  salt  is  wanted.  The  application  of 
heat  assists  the  solution  of  the  precipitate  in  the  acid.  By  these 
means  peracetate,  peroxalate,  pertartrate,  &c,  may  be  obtained 
either  for  practical  use  or  experiments. 

The  following  is  the  reaction  of  different  substances  upon 
the  pro  and  per  salts  of  iron. 

Protosalts. — Potash,  soda,  and  ammonia  give  at  first  a 
gray-white  precipitate,  passing  into  green,  then  bluish,  and 
which  by  exposure,  finally  becomes  brown. 

Carbonates  of  these  alkalies  produce  precipitates,  which  pass 
through  the  same  changes  as  the  alkalies  themselves. 

Yellow  prussiate  of  potash  .  A  gray-white  precipitate,  which, 

by  exposure,  becomes  blue. 

Eed  prussiate  of  potash  .  .  An  immediate  dark-blue  precipi- 
tate. 

Solution  of  galls  A  blue-black,  not  changed  by 

standing. 

11 


162 


COBALT 


Persalts  of  Iron. — Alkalies,  and  carbonates  of  the  alka- 
lies, all  produce  dark-brown  precipitates. 

Yellow  prussiate  of  potash  .  An  immediate  dark-blue  precipi- 
tate. 

Bed  prussiate  of  potash  .    .  No  precipitate,  but  the  solution 

becomes  green. 

Solution  of  galls     ....  Black,   passing  to   brown  by 

standing. 

The  difference  between  the  action  of  red  and  yellow  prus- 
siates  will  be  remarked. 


Cobalt  (Co  29.5). 

Cobalt  generally  occurs  in  nature  in  combination  with  ar- 
senic and  sulphur,  and  accompanied  by  other  metals.  The 
mineral  in  which  it  occurs  was  long  known  to  miners,  and  was 
called  by  them  kohalds,  or  evil  spirit  of  the  mines,  because  its  ap- 
pearance often  deceived  them  by  giving  a  favorable  impression 
of  mines  which  turned  out  erroneous,  the  cobalt  being  taken 
for  something  else.  Its  distinct  character  as  a  metal  was  dis- 
covered in  1733.  Its  oxide  has  long  been  extensively  used  for 
giving  a  blue  color  to  glass  and  porcelain.  As  a  metal  it  is 
brittle,  of  a  reddish-gray  color,  and  little  more  flexible  than 
iron.    It  has  two  oxides  similar  to  iron. 

Protoxide  Co  0 

Peroxide   Co303.* 

But  there  is  no  persalt  of  cobalt  known  equivalent  to  the  per- 
oxide. 

Cobalt  is  easily  dissolved  in  either  hydrochloric  or  nitric 
acids,  and  forms  pink-colored  solutions  which  produce  crystals 
of  a  beautiful  red  color.  Solutions  of  these  salts  form  sympa- 
thetic inks.  By  writing  upon  clean  paper  with  one  of  these  solu- 
tions, the  writing  is  invisible  when  partly  dry ;  but  by  heating 
the  paper  before  a  fire,  the  writing  becomes  blue,  and  disappears 
again  on  cooling.  If  the  heat  applied  be  too  strong,  the 
writing  becomes  black  and  permanent,  a  significan|fcract  to  the 
dyer.  Cobalt  does  not  dissolve  easily  in  sulphuric  acid  ;  but  a 
sulphate  may  be  prepared  by  adding  sulphuric  acid  to  the 
oxide  or  carbonate,  which  is  formed  by  adding  a  carbonate  or 
caustic  alkali  to  the  nitrate  or  hydrochlorate  of  cobalt.  The  sul- 
phate salt  has  also  a  pink  color,  but  is  not  so  generally  used  as 

*  These  oxides  appear  to  combine  together  in  various  proportions. 


NICKEL. 


163 


the  others.  Salts  of  any  of  the  acids  may  be  prepared  by  dis- 
solving the  oxide  or  carbonate.  They  are  all  affected  by  heat 
in  the  manner  described. 

Some  of  these  salts  might  be  very  usefully  employed  in  dye- 
ing, were  they  obtained  at  a  sufficiently  low  cost ;  but  they  are 
progressively  becoming  cheaper,  and  may  therefore  ere  long 
be  made  available  in  the  dye-house. 

A  preparation  of  cobalt  is  used  in  bleaching,  as  smalt  blue. 
It  is  a  compound  of  oxide  of  cobalt  and  alumina,  prepared  by 
mixing  a  solution  of  salt  of  cobalt  and  alum,  and  precipitating 
them  together  by  an  alkaline  carbonate,  as  carbonate  of  soda, 
drying  the  precipitate,  and  subjecting  it  to  a  red  heat.  The 
process  gives  a  beautiful  blue  mass,  which  is  ground  to  an  im- 
palpable powder,  and  mixed  commonly  with  some  carbonate 
of  lime  (chalk).  Salts  of  cobalt  give  the  following  reactions 
with  other  substances  : — 

Potash,  soda  and  ammonia   .    .  A  green  color  by  a  little 

exposure. 

Carbonates  of  the  alkalies    .    .  Reddish  precipitates,  which 

become  blue  by  boiling. 

•  Phosphate  of  soda  Blue  precipitate. 

Yellow  prussiate  of  potash   .    .  Green   precipitate,  which 

changes  to  gray. 
Red  prussiate  of  potash    .    .    .  Reddish-brown  precipitate. 
Sulphurets  of  the  alkalies  .    .    .  Black  precipitates. 

The  slightest  trace  of  cobalt  may  be  detected  by  the  blow- 
pipe, by  fusing  a  little  borax,  and  adding  a  little  of  the  sub- 
stance suspected  to  contain  cobalt;  if  it  be  really  present,  it 
communicates  to  the  borax  a  blue  color,  more  or  less  intense. 

Nickel  (Ni  29.6). 

Nickel  occurs  in  nature  combined  with  arsenic,  iron,  cobalt, 
and  sulphur.  It  was  discovered  in  1751.  Isolated,  it  is  a 
silver-white  metal,  ductile,  and  malleable,  and  requires  a  heat 
nearly  equal  to  that  of  iron  to  melt  it.  It  is  much  used  in  the 
arts  for  alloying  with  other  metals.  It  is  the  principal  con- 
stituent of  German  silver.  Nickel  combines  with  oxygen  in 
two  proportions. 

Protoxide  Ni  0. 

Peroxide  Ni203. 

There  are  no  persalts  of  nickel  equivalent  to  the  peroxide 
known. 


161 


ZINC. 


Sulphate  of  Nickel. — Sulphuric  acid  dissolves  nickel  with 
difficulty.  When  the  sulphate  is  required,  the  acid  is  applied 
to  the  carbonate  or  oxide  of  the  metal ;  in  this  state  it  is  easily 
dissolved,  and  forms  a  beautiful  green-colored  solution. 

Chloride  of  Nickel. — Hydrochloric  acid,  when  dilute,  dis- 
solves nickel,  and  forms  a  chloride;  the  solution  is  emerald 
green. 

Nitrate  of  Nickel. — Nitric  acid  dissolves  nickel  easily, 
and  may  be  called  its  true  solvent;  the  product  is  the  nitrate, 
of  which  the  solution  is  also  emerald  green.  All  these  salts 
crystallize. 

Carbonate  of  Nickel. — This  salt  is  prepared  by  precipi- 
tating the  nitrate  by  a  carbonated  alkali,  as  carbonate  of  soda 
or  potash.  It  is  a  greenish-colored  precipitate.  The  common 
means  of  preparing  the  salts  of  nickel  is  by  dissolving  in  nitric 
acid,  then  precipitating  and  washing  the  precipitate;  by  adding 
the  required  acid  the  precipitate  is  dissolved.  "The  acetate,  or 
oxalate,  or  any  of  the  other  salts,  may  easily  be  prepared  in  this 
way.  The  use  of  any  of  these  salts  in  the  dye-house  is  very 
limited.    Their  solutions  are  precipitated  as  follows: — 


Alkalies 


Ammonia,  in  excess  . 
Carbonate  of  the  alkalies 
Yellow  prussiate  of  potash 
lied  prussiate  of  potash 
Solution  of  galls 
Phosphate  of  soda 
Sulphuret  of  the  alkalies 


An  apple-green  precipitate  of 
hydrated  oxide,  insoluble  in 
excess. 

Blue  solution. 

Green  precipitate. 

Greenish-white  precipitate. 

Yellow-green  precipitate. 

No  precipitate. 

White  precipitate. 

Black  precipitate. 


Zinc  (Zn  32.6). 

Zinc  was  discovered  in  the  sixteenth  century.  It  is  very 
abundant  in  nature,  in  combination  with  sulphur,  and  with  car- 
bonic acid.  With  the  former,  it  is  the  ore  called  blende  or  black 
jack  ;  with  the  latter,  it  is  calamine.  Zinc  is  a  white  metal  with 
a  shade  of  blue,  brittle,  and  of  a  crystalline  structure.  When 
heated  from  the  boiling  point  of  water  to  300°,  it  is  ductile,  and 
admits  of  being  rolled  into  sheets,  in  which  state  it  has  become 
a  most  useful  metal  in  the  arts.  At  a  red  heat  it  rises  into 
vapor,  and  takes  fire  in  air,  burning  with  a  white  flame.  It  is 
much  used  along  with  copper  for  making  the  common  alloy 
known  as  brass. 

Zinc  combines  with  oxygen  in  several  proportions;  but  the 


NITRATE  OF  ZINC. 


165 


only  one  of  its  oxides  which  has  been  studied  is  the  protoxide 
==Zn  O.  The  salts  found  are  the  protosalts,  equivalent  to  this 
oxide. 

Protoxide  of  zinc  may  be  obtained  either  by  burning  the 
metal,  or  by  precipitating  it  by  an  alkali  from  its  acid  solu- 
tions. It  forms  a  white  powder,  which  is  soluble  in  all  the 
caustic  alkalies. 

Chloride  of  Zinc. — Hydrochloric  acid  acts  rapidly  upon 
zinc,  evolving  hydrogen  gas,  thus: — 

Hydrochloric  acid   Hydrogen  gas. 

Zinc  Zn"^^  Chloride  of  zinc. 

It  crystallizes  in  white  crystals,  which  are  very  deliquescent, 
and  often  used  on  account  of  this  property  for  keeping  sub- 
stances damp.  It  is  even  said  to  be  employed  by  tobacconists 
for  keeping  snuff  and  tobacco  moist,  a  dangerous  and  most 
reprehensible  practice,  if  true.  It  is  now  very  extensively  used 
for  soldering  instead  of  rosin. 

Sulphate  of  Zinc. — This  salt  is  easily  prepared  by  acting 
upon  zinc  with  sulphuric  acid  slighty  diluted:  the  action  is 

Sulphuric  acid  .    .  I  |Fq*  Hydrogen  gas. 

Zinc  Zn..   Sulphate  of  zinc. 

It  crystallizes  in  white-colored  crystals,  which  contain  seven 
proportions  of  water  of  crystallization,  and  dissolve  in  two  and 
a  half  times  their  weight  of  cold  water.  It  is  known  in  com- 
merce as  white  vitriol,  white  copperas,  and  is  produced  in  great 
quantities  in  the  soldering  of  platinum  vessels.  Articles  of 
this  kind  are  soldered  by  the  flame  of  the  oxyhydrogen  blow- 
pipe, for  which  the  hydrogen  required  is  prepared  by  zinc  and 
sulphuric  acid,  and  thus  the  sulphate  becomes  a  product. 

Nitrate  of  Zinc. — This  salt  is  easily  prepared  by  acting 
upon  the  metal  with  nitric  acid;  it  is  a  crystalline  salt  very 
deliquescent,  but  not  much  used. 

Acetates,  oxalates,  and  salts  of  such  milder  acids,  may  be 
prepared  either  by  digesting  the  metal  in  the  acids,  or  by  act- 
ing upon  the  oxide  or  carbonate  found  as  a  precipitate.  The 
salts  of  zinc  are  not  much  used  in  the  dye-house;  the  pre- 
cipitates formed  from  them  are  nearly  white ;  the  sulphate 
is  used  in  several  operations,  where  its  elements  may  act  an 
important  part  without  affecting  the  tint,  as  in  the  operations 
of  dyeing  chrome  yellows,  &c.  It  is  also  used  by  calico-printers 
in  some  of  the  operations  of  discharging. 

The  salts  of  zinc  act  towards  other  substances  as  follows: — 


166 


CADMIUM. 


Potash,  soda,  and  ammonia  .  White  precipitate,  easily  dis- 
solved in  an  excess  of  the 
alkali. 

Carbonates  of  the  alkalies  .  .  White  precipitate,  not  soluble 

in  excess,  but  soluble  in 
caustic  alkalies. 

Yellow  prussiate  of  potash  .  .  White  precipitate. 
Eed  prussiate  of  potash    .  .  .  Yellowish-precipitate;  fades 

in  the  air. 

Solution  of  galls  No  precipitate. 

Sulphurets  of  alkalies  White  precipitate. 

Chromic  acid  A  purple-brown  precipitate. 

Cadmium  (Cd  56). 

This  metal  was  discovered  in  1818;  it  is  found  only  in  small 
quantities,  and  often  combined  with  zinc.  The  metal  some- 
what resembles  tin  in  color;  it  is  also  soft  and  flexible,  and 
makes  a  crackling  noise  when  bent.  It  melts  easily,  and  passes 
off  as  a  gas  at  a  heat  of  about  600°.  It  combines  with  oxygen 
in  equal  proportions,  forming  the  protoxide  (Cd  O),  which  has 
an  orange  color,  and  is  easily  obtained  by  burning  the  metal 
in  air,  er  by  precipitation  from  acid  solution  by  a  caustic  alkali. 
Prepared  in  this  way,  it  is  a  white  hydrate,  and  has  one  pro- 
portion of  water  combined  with  it.  This  oxide  is  soluble  in 
ammonia,  but  not  in  soda  or  potash. 

Cadmium  is  acted  upon  like  zinc,  both  by  sulphuric  and 
hydrochloric  acids  ;  and  forms  crystallizable  salts.  Nitric  acid 
acts  readily  upon  the  metal  to  form  the  nitrate,  which  is  crys- 
tallized with  difficulty.  All  these  salts  give  white-colored 
crystals.  The  salts  of  the  milder  acids,  as  the  acetate,  the 
oxalate,  &c,  may  be  obtained  by  dissolving  the  precipitated 
oxide  or  carbonate  in  the  particular  acid. 

Potash  and  soda,  and  their  carbonates,  give  white  precipi- 
tates, not  soluble  in  an  excess  of  reagent. 

Ammonia — white  precipitate  soluble  in  excess.  (The  oxide 
and  carbonate,  precipitated  by  the  fixed  alkalies,  are  all  soluble 
in  ammonia.) 

Yellow  prussiate  of  potash  .  .  White  precipitate. 

Eed  prussiate  of  potash    .  .  .  Yellow  precipitate. 

Solution  of  galls   No  precipitate. 

Sulphurets  of  the  alkalies  .  .  Beautiful  yellow  precipitate. 


PROTOXIDE  OF  COPPER. 


167 


Copper  (Ou  31.7). 


This  is  a  very  abundant  and  useful  metal,  and  was  known 
in  the  earliest  times.  It  is  found  in  nature  in  great  quantities, 
in  combination  with  sulphur,  oxygen,  and  carbonic  acid ;  and 
is  separated  from  these  combinations  by  various  processes  of 
roasting  and  fusing.  Copper  is  of  a  red  color;  is  very  malle- 
able and  ductile,  and  only  inferior  to  iron  in  tenacity.  It 
requires  a  heat  of  about  1900°  to  fuse  it.  It  combines  with 
oxygen  in  two  proportions,  namely: — 

Suboxide  or  dinoxide  Cu20. 


The  suboxide  is  of  a  reddish  brown  color,  which  is  not  changed 
by  the  air.  If  acted  upon  by  dilute  acids,  a  protosalt  is 
formed,  and  in  strong  hydrochloric  acid  there  is  formed  a 
subchloride=Cu2  CI.  This  is  a  greenish  or  nearly  colorless 
solution,  which  undergoes  decomposition  by  dilution;  and  if 
precipitated  by  an  alkali,  oxygen  is  absorbed,  and  protoxide  is 
formed.  If  a  portion  of  suboxide  be  put  into  a  stoppered  bottle 
with  ammonia,  it  is  dissolved,  and  the  solution  is  colorless  at 
first,  but  by  admitting  air  it  is  oxidized,  and  the  solution  be- 
comes blue. 

Protoxide  of  Copper  is  black,  and  is  formed  upon  the 
surface  of  metallic  copper  when  brought  to  a  red  heat,  and 
exposed  to  the  air ;  or  it  may  be  obtained  by  exposing  the 
carbonate,  acetate,  or  nitrate,  to  a  red  heat.  Alkalies  added  to 
solutions  of  copper,  precipitate  the  oxide  as  a  hydrate  of  a  blue 
color,  which  becomes  black  by  boiling.  Oxide  of  copper  dis- 
solves readily  in  ammonia,  and  gives  a  deep  blue-colored  solu- 
tion. 

Copper  combines  with  nearly  all  the  acids,  and  the  salts 
produced  are  generally  blue  or  green.  Sulphuric  acid,  when 
cold,  does  not  dissolve  copper,  but  at  a  boiling  heat  it  acts 
upon  it  readily,  a  portion  of  the  acid  suffering  decomposition, 
as  under: — 


Protoxide 


Cu  0. 


fS... 
0... 

One  proportion  of  sulphuric  ,  0... 
acid  decomposed  j  0... 


Sulphurous  acid 
gas. 


O... 
H.. 

One  proportion  of  sulphuric  ( S04 
acid  (H.. 
One  proportion  of  copper  Cu. 


.Water. 


Water. 

Sulphate  of  copper 


168 


NITRATE  OF  COPPER. 


Sulphate  of  Copper  yields  deep  blue  crystals,  containing 
five  proportions  of  water,  four  of  which  are  given  off  by  heat- 
ing the  crystals  to  212°,  at  which  temperature  they  become 
white.  They  are  soluble  in  four  times  their  weight  of  cold 
water,  and  in  twice  their  weight  of  boiling  water.  The  salt  is 
prepared  on  the  large  scale,  in  the  same  manner  as  the  sulphate 
of  iron  ;  that  is,  from  the  sulphurets  of  the  metal.  Great  quan- 
tities of  it  are  produced  by  the  metal  workers  in  Birmingham 
and  elsewhere,  in  their  cleaning  and  bronzing  operations, 
which  are  effected  by  the  action  of  acids  upon  copper  or  its 
alloys.  As  obtained  in  commerce,  it  is  often  impure,  and  is 
often  contaminated  with  iron,  a  very  injurious  ingredient  for 
most  of  the  purposes  to  which  this  salt  is  applied  in  the  dye- 
house.  This  impurity  can  be  detected  by  dissolving  a  little 
of  the  salt  in  pure  water,  and  adding  ammonia  in  excess  ;  on 
filtering  through  water,  and  washing  the  filter,  the  iron  will  be 
obtained  as  a  brown  precipitate  of  peroxide.  If  the  salt  con- 
tains much  iron,  it  ought  to  be  rejected.  Zinc  is  often  present, 
but  it  has  no  deleterious  effects  farther  than  in  lessening  the 
value  of  the  salt.  Sulphate  of  copper  is  known  in  commerce 
and  in  the  dye-house  as  blue  vitriol,  Roman  vitriol,  and  blue- 
stone. 

Nitrate  of  Copper. — Nitric  acid  dissolves  copper  easily, 
forming  the  nitrate ;  the  action  is  similar  to  that  by  which  the 
nitrate  of  iron  is  produced. 


1  proportion  of  nitric  acid  < 


N... 
0... 
O... 

o... 

0... 
0... 
0  .. 
H... 

3  proportions  of  nitric  acid 


3  proportions  of  copper 


|  3Cu. 


Binoxide  of  nitrogen. 


Water. 
3  Water. 

3  Nitrate  of  copper. 


Nitrate  of  copper  crystallizes  in  deep  blue  crystals,  which 
deliquesce  in  the  air,  and  are  accordingly  very  soluble  in  water. 
The  salt  acts  rapidly  upon  tin;  if  a  small  crystal  be  crushed, 
slightly  moistened,  and  wrapped  in  tin  foil,  combustion  takes 
place  by  the  rapid  oxidation  of  the  tin.  The  salts  of  copper 
are  very  useful  for  oxidizing  vegetable  matters  in  solution,  and 
are  often  used  for  that  purpose  in  the  dye-house. 

Chloride  of  Copper  is  made  by  digesting  oxide  of  copper 


LEAD. 


169 


in  hydrochloric  acid,  by  which  a  double  decomposition  takes 
place,  as  follows: — 


Hydrochloric  acid 
Oxide  of  copper 


Water. 


Chloride  of  copper. 


The  solution  of  this  salt  is  green,  but  it  crystallizes  from  this 
solution  in  blue-colored  crystals. 

Acetate  of  Copper  {verdigris)  is  prepared  by  exposing  sheets 
of  copper  to  the  action  of  acetic  acid  {vinegar),  sometimes  in 
solution,  but  more  commonly  in  vapor.  The  salt  is  obtained 
in  beautiful  dark-green  crystals ;  in  this  state  it  is  a  subacetate, 
having  one  acetic  acid  to  two  of  copper.  Acetic  acid  combines 
with  copper  in  various  proportions,  and  the  verdigris  of  com- 
merce is  often  composed  of  several  salts,  not  by  adulteration, 
but  formed  in  the  process  of  manufacture. 

Oxalate  of  Copper  is  of  a  light-green  color,  and  is  prepared 
by  digesting  oxide  of  copper  in  oxalic  acid. 

Arseniate  and  the  Arsenite  of  Copper  are  salts  of  a  light- 
green  color,  formed  during  the  dyeing  of  arsenic  greens — blue- 
stone  sages  or  ScheeWs  green — for  which  the  goods  are  passed 
through  strong  solutions  of  arsenic  and  copper,  and  alkalies. 
That  these  greens  are  still  dyed  argues  little  for  mercantile 
morality.  This  process  of  dyeing  is  dangerous,  and  the  wind- 
ing of  the  yarns,  and  other  operations  that  follow,  are  more  so, 
and  produce  much  serious  mischief  to  the  operatives. 

Copper  salts  produce  the  following  reactions: — 

Potash  and  soda  Greenish-blue  precipitates,  be- 
come black  with  boiling. 


Ammonia  

Carbonate  of  alkalies 
Yellow  prussiate  of  potash 
Red  prussiate  of  potash  . 
Solution  of  galls   .    .  . 
Sulphurets  of  alkalies  . 


Deep-blue  liquid. 
Green  precipitate. 
Dark-brown  precipitate. 
Yellow-green  precipitate. 
Browrn  precipitate. 
Black  precipitates. 


Lead  (Pb  103.6). 

This  metal  exists  abundantly  in  nature,  mostly  in  combina- 
tion with  sulphur,  from  which  it  is  separated  by  exposing  the 
ore  to  a  gentle  heat;  the  sulphur  becomes  oxidized,  and  passes 
off  as  sulphurous  acid,  and  the  lead  melts,  and  runs  off  by  a 
channel  prepared  for  it. 

Lead  has  a  bluish-gray  color,  is  soft,  and  very  malleable ;  it 


170 


PROTOXIDE  OF  LEAD. 


does  not  oxidate  readily  in  the  air,  except  at  the  water-line 
when  it  is  partially  immersed  in  that  fluid,  and  more  rapidly 
still  when  the  water  is  soft  and  pure.  Hence  lead  vessels  should 
not  be  used  to  hold  water  for  domestic  use,  as  the  oxides  of 
lead  are  all  very  poisonous. 

Lead  combines  with  oxygen  in  various  proportions. 

Suboxide  of  lead  is  the  grayish-blue  crust,  formed  upon 
the  surface  of  lead  exposed  to  the  air,  and  consists  of  two 
equivalents  of  lead  and  one  of  oxygen,  Pb2  O.  It  may  be 
prepared  artificially,  by  burning  oxalate  of  lead  in  a  retort; 
the  suboxide  remains  as  a  dark  gray  powder. 

Protoxide  of.  Lead  consists  of  lead  and  oxygen  in  equal 
proportions,  =  Pb  0.  It  may  be  obtained  by  exposing  metallic 
lead  at  a  red  heat  to  a  current  of  air ;  the  oxygen  of  the  air 
combines  with  the  lead,  and  forms  with  it  a  semifluid  mass. 
As  it  cools,  it  crystallizes  in  concretions  of  a  greenish-yellow 
color.  It  is  obtained  on  the  large  scale  by  cupellation — a 
process  of  fusion  to  which  lead  is  subjected  in  the  process  of 
extracting  the  small  admixture  of  silver  it  commonly  contains. 
The  process  is  conducted  as  follows :  A  quantity  of  lead  is  put 
upon  a  flat  vessel  made  of  bone-ashes  (burned  bones)  placed  in 
a  furnace ;  when  the  lead  is  melted,  a  strong  current  of  air  is 
blown  upon  the  surface,  which  rapidly  oxidates  the  metal ;  at 
the  same  time,  the  force  of  the  current  blows  the  oxide  off, 
which  runs  over  the  side  of  the  vessel  like  water.  The  silver, 
not  being  capable  of  oxidation,  by  this  means  is  ultimately  left 
pure  upon  the  bottom  of  the  vessel.  Lead  is  continually  added, 
until  the  silver  remaining  nearly  fills  this  bone-ash  vessel,  which 
is  technically  termed  a  cupel. 

When  the  protoxide  of  lead  is  kept  for  some  time,  it  falls 
into  a  brick-red  scaly  crystalline  powder,  known  in  commerce 
as  litharge.  This  is  the  principal  oxide  from  which  the  salts 
of  lead  are  prepared  for  the  dye-house ;  but  it  is  generally  to 
some  extent  contaminated  with  iron,  copper,  and  red  lead,  and 
is  also  subject  to  much  intentional  adulteration.  Litharge,  of 
good  quality,  possesses  a  crystalline  lustre,  and  is  completely 
soluble  by  digestion  in  nitric  acid.  The  amount  of  adultera- 
tion, if  it  be  brickdust,  may  thus  be  ascertained,  as  it  remains 
insoluble,  and,  by  adding  ammonia  to  the  solution,  the  lead  is 
precipitated;  if  iron  be  present,  the  precipitate  will  have  a  brown 
color ;  if  copper,  the  solution  will  be  blue,  but  none  of  these 
are  deleterious  to  the  dye.  The  protoxide  of  lead  is  also  ob- 
tained by  adding  a  caustic  alkali  to  a  solution  of  a  salt  of  lead ; 
the  oxide  is  precipitated  as  a  white  powder,  soluble  in  an  excess 
of  caustic  alkali,  and  also  in  solutions  of  the  alkaline  earths,  as 
lime,  with  which  it  forms  compounds  more  or  less  soluble. 


ACETATE  OF  LEAD. 


171 


Peroxide  of  Lead  consists  of  two  equivalents  of  oxygen 
and  one  of  lead  =  Pb  02.  It  may  be  obtained  by  digesting 
litharge  in  a  boiling  solution  of  chloride  of  lime  {bleaching 
powder).  It  is  a  powder  of  a  dark  brown  color,  and  is  not  used 
for  preparing  any  salts  of  lead. 

What  is  termed  the  fourth  oxide  of  lead,  consists  of  Pb3  04; 
but  this  is  not  generally  considered  to  be  a  direct  combination 
of  oxygen  and  lead  in  these  proportions,  but  a  mixture  of  the 
second  and  third  oxide  just  described,  in  the  proportion  of  two 
of  the  protoxide  to  one  of  the  peroxide,  2  Pb  O  +  Pb  02,  which 
may  be  separated  by  digestion  in  dilute  nitric  acid  ;  the  acid 
combining  with  the  protoxide,  and  liberating  the  peroxide  which 
remains  undissolved.  Whether  the  view  we  have  stated  of  its 
constitution  be  correct  or  not,  is  not  very  important,  as  this 
oxide  is  not  much  used  in  the  dye-house.  It  is  known  in  com- 
merce as  red  lead,  or  minium. 

Carbonate  of  Lead  ( White  had)  is  prepared  on  the  large 
scale  by  exposing  thin  sheets  of  lead  to  the  vapors  of  vinegar ; 
the  acid  is  decomposed  and  forms  carbonic  acid,  which  combines 
with  the  lead.  This  salt  is  sometimes  used  for  preparing  salts 
of  lead,  by  dissolving  it  in  the  acid  the  salt  of  which  is  required. 

Nitrate  of  Lead  is  prepared  by  dissolving  litharge,  or 
metallic  lead,  in  nitric  acid,  and  evaporating  the  solution,  which 
leaves  a  crystalline  mass,  the  crystals  of  which  are  white  and 
generally  opaque,  and  soluble  in  7|  parts  of  cold  water.  The 
nitrate  of  lead,  when  prepared  in  this  way,  contains  one  propor- 
tion of  oxide,  and  one  of  nitric  acid  ;  but  by  boiling  the  salt  for 
some  time  over  litharge,  the  acid  combines  with  two,  three,  or 
even  six  proportions  of  lead,  forming  what  are  termed  basic 
salts.  This  fact  has  been  known  to  practical  dyers  for  many 
years,  and  is  made  available  for  the  purpose  of  dyeing  orange 
color  and  dark  shades  of  yellow. 

Acetate  of  Lead  (Sugar  of  Lead)  may  be  obtained  by  ex- 
posing metallic  lead  to  the  action  of  acetic  acid,  either  as  a 
liquor  or  as  a  vapor,  and  to  the  air ;  a  portion  of  the  acid  is 
decomposed,  and  carbonate  of  lead  is  formed,  which  is  then 
easily  decomposed  by  another  portion  of  the  acid;  the  latter 
combining  with  the  lead,  forms  acetate  of  lead,  and  the  car- 
bonic acid  is  evolved. 

Acetate  of  lead  is  prepared  extensively  by  a  variety  of 
modes.  The  first  is  by  immersing  a  number  of  sheets  of  lead 
in  vinegar,  so  arranged  that  the  uppermost  sheets  are  exposed 
to  the  action  of  the  air.  When  they  become  covered  with  the 
crust  of  carbonate,  they  are  shifted  to  the  bottom  of  the  vat, 
where  the  acid  decomposes  the  carbonate  aud  forms  acetate, 


172 


ACETATE  OF  LEAD. 


while  the  succeeding  sheets  are  being  exposed  to  the  same 
course  of  action. 

Another  process  is  to  expose  sheets  of  lead  to  the  vapor  of 
vinegar ;  the  carbonate  formed  is  collected  and  immersed  in 
strong  vinegar.  In  both  these  processes,  when  the  acid 
appears  to  be  saturated,  or  when  it  ceases  to  decompose  the 
carbonate,  the  solution  is  drawn  into  proper  vessels  and  allowed 
to  crystallize. 

Another  process  is  to  dissolve  litharge  in  strong  vinegar  to 
saturation.  This  is  done  by  gradually  sprinkling  the  litharge 
in  a  vessel  of  vinegar  subjected  to  a  boiling  heat ;  the  vinegar 
is  constantly  stirred,  to  prevent  the  adhesion  of  the  litharge  to 
the  bottom  and  sides  of  the  boiler.  When  a  sufficient  quan- 
tity is  dissolved,  a  moderate  quantity  of  cold  water  is  poured 
into  the  solution,  reducing  it  a  little  below  the  boiling  point, 
and  it  is  allowed  to  settle;  the  clear  fluid  is  then  drawn  off 
into  a  separate  vessel  and  allowed  to  crystallize.  If  the  solu- 
tion be  colored,  it  is  whitened  by  filtration  through  bone-black. 
Common  unrectified  wood  vinegar,  or  pyroligneous  acid,  is 
much  used  for  the  preparation  of  acetate  of  lead  for  the  dye- 
work.  It  is  known  in  the  dye-house  by  the  appellation  of 
brown  sugar. 

Basic  salts  or  subacetates,  are  made  by  boiling  common 
acetate  of  lead  with  litharge.  The  tribasic  acetate,  a  combina- 
tion of  three  of  lead  to  one  of  acid,  is  the  best  salt  for  dyeing 
orange,  deep  yellow,  and  amber.  It  is  prepared  in  the  dye- 
house  by  boiling  a  solution  of  sugar  of  lead  with  litharge;  and 
adding  to  this  a  little  lime.  The  proportions,  however,  vary 
in  different  dye-houses.  Those  which  ought  to  be  employed 
to  produce  the  tribasic  acetate,  are  six  parts'  of  crystallized 
acetate  of  lead,  eight  of  litharge,  and  thirty  of  water,  boiled 
till  the  litharge  is  dissolved.  The  addition  of  small  quantities 
of  lime  causes  a  loss,  as  the  lime  combines  with  part  of  the 
acetic  acid  forming  acetate  of  lime,  which,  if  these  proportions 
have  been  used,  would  prevent  some  of  the  litharge  from  being 
dissolved.  If  the  mixture  be  not  long  enough  boiled,  or  if  the 
proportion  of  litharge  be  too  small,  the  addition  of  lime  insures 
the  conversion  of  the  acetate  of  lead  into  the  tribasic  state, 
though  it  is  to  be  observed  that  this  will  be  at  the  expense  of 
a  portion  of  the  lead  intended  for  producing  the  color.  We 
have  experienced  much  annoyance  from  this  source  ;  and  it 
is  well  known  in  the  trade,  that  when  the  lead  is  hastily 
prepared  for  orange,  it  is  a  cause  of  great  anxiety,  and  the 
color  obtained  is  frequently  defective.  As  this  is  rather  an 
important  point  in  the  economy  of  the  dye-house,  we  shall  ex- 
plain our  view  of  the  matter.    If  the  proportions  recommended 


CHLORIDE  OF  LEAD. 


173 


above  be  used,  the  following  is  the  result — and  we  must  bear 
in  mind  that  while  the  oxide  of  lead  forms  the  basis  of  the  dye, 
the  acid  merely  holds  the  lead  in  solution  :  The  six  pounds  of 
acetate  of  lead  are  composed  of  4  lbs.  oxide  of  lead,  and  2  lbs. 
acetic  acid  ;  but  when  the  8  lbs.  of  litharge  are  dissolved,  or, 
as  dyers  say,  taken  up,  the  tribasic  salt  will  consist  of  12  lbs. 
of  oxide  of  lead  and  2  lbs.  of  acetic  acid  ;  that  is,  every  ounce 
of  acid  holds  in  solution  6  ounces  oxide  of  lead.  Now,  if  a 
little  lime,  as  we  have  often  remarked,  be  put  in  along  with 
the  litharge,  the  result  will  be  as  follows  :  Suppose  that  50  lbs', 
of  cotton  are  to  be  dyed  orange,  and  that  if  consumed  the  6  lbs. 
acetate  of  lead  prepared  as  now  stated,  to  give  it  a  good  color. 
If  1J  ounces  of  lime  be  mixed  in,  they  will  combine  with  3 
ounces  of  acid  ;  in  this  way  18  ounces  of  oxide  of  lead  are  not 
taken  up,  and  are  therefore  ineffective  in  the  production  of  the 
color ;  while  at  the  end  of  the  process,  the  dyer  is  surprised  to 
find  his  color  poor.  We  may  notice  that  lead  in  the  basic 
state  is  not  held  in  combination  by  a  very  great  affinity,  and 
thus  a  very  little  counteractive  influence  precipitates  it.  The 
presence  of  sulphates  or  carbonates  in  the  water,  which  almost 
all  water  contains,  precipitates  the  lead  ;  hence  the  reason  that 
often,  when  the  clear  acetate  solution  is  poured  into  a  tub  of 
water;  the  contents  become  milk-white  by  the  formation  of  an 
insoluble  carbonate  or  sulphate.  The  lead  is  all  lost  for  the 
time,  as  it  is  rendered  insoluble  and  useless  as  a  dye.  Every 
ounce  of  carbonate  renders  useless  five  ounces  of  lead.  The 
softest  water  should  be  used  for  the  lead  solution,  as,  for  ex- 
ample, the  condensed  steam  from  an  engine.  When  much  lime 
is  added,  it  dissolves  the  lead,  and  forms  a  mordant  quite  as 
good,  if  not  superior,  to  that  described,  as  we  will  have  occa- 
sion more  fully  to  indicate  when  we  come  to  treat  of  the  pro- 
cesses for  dyeing  oranges  and  yellows.  Alkaline  salts  of  lead 
and  oxide  of  lead,  dissolved  in  alkalies,  are  now  becoming 
more  generally  used  than  the  acid  salts,  and  are  superior  for 
most  purposes. 

Sulphate  of  Lead. — Sulphuric  acid,  when  hot  and  con- 
centrated, dissolves  lead ;  but  the  sulphate  is  precipitated  by 
dilution.  It  is  an  insoluble  white  powder,  easily  formed  by 
adding  a  solution  of  a  soluble  sulphate,  as  that  of  an  alkali,  to 
any  salt  of  lead. 

Chlokide  of  Lead. — Lead  dissolves  slowly  in  hydrochloric 
acid,  forming  a  chloride  which  requires  135  times  its  weight 
of  cold  water  to  dissolve  it.  Several  sub-chlorides  of  lead  are 
also  capable  of  being  formed,  but  they  are  nearly  all  insoluble 
in  water. 

All  the  soluble  salts  of  lead  are  poisonous,  and  have  a  sweetish 


174 


BISMUTH. 


taste,  except  the  sulphate,  which  is  inert.  Their  reactions  with 
other  substances  are  as  follows: — 

Soda  and  potash,  give   .  . 

Lime  

Ammonia  

Carbonates  of  alkalies  .  . 

Oxalic  acid  

Yellow  prussiate  of  potash 
Eed  prussiate  of  potash  .  . 
Solution  of  galls  .... 
Chromates  of  potash  .  .  . 
Iodide  of  potassium  .  .  . 
Sulphurets  of  the  alkalies  . 

Testing  the  Value  of  Lead  Salts. — A  very  simple 
method  of  testing  the  value  of  salts  of  lead,  that  is,  of  ascer- 
taining the  quantity  of  lead  in  a  solution,  is  to  dissolve  say  10 
grains  of  bichromate  of  potash  (red  chrome)  in  hot  water,  and 
put  the  solution  into  a  tall  glass  jar;  then  take  a  given  weight, 
say  100  grains  of  the  lead  salt,  whether  acetate  or  nitrate,  and 
dissolve  in  100  measures  (by  the  alkalimeter)  of  water ;  add 
this  gradually  to  the  chrome  solution  until  the  liquor  above 
the  precipitate  becomes  colorless,  or  until  a  drop  of  the  liquor 
added  to  a  drop  of  the  lead  solution  on  a  glass  plate  is  not 
turned  yellow\  The  number  of  graduations  taken  to  effect  this 
is  noted ;  then,  as  every  148.6  of  bichromate  of  potash  is  equal 
to  379.4  acetate  of  lead,  or  830  nitrate  of  lead,  the  quantity 
required  by  the  10  grains  chrome  is  easily  calculated — being 
for  acetate  25.6,  and  for  nitrate  23  grains.  All  the  solution 
required  above  these  measures  will  indicate  impurities.  The 
average  of 

Commercial  nitrate  requires  24  grains. 
"  white  sugar,       27  " 

"  brown  sugar,      28  " 

The  quantity  of  lead  in  a  solution  is  tested  in  the  same  way. 

Bismuth  (Bi  213  or  106.5). 

This  metal  occurs  in  nature  in  the  metallic  state,  and  also  in 
combination  with  other  substances.    When  found  in  the  me- 


White  precipitates,  soluble  in  ex- 
cess. 

White  precipitate,  soluble  in  ex- 
cess. 

White  precipitate,  insoluble  in  ex- 
cess. 

White  precipitates,  insoluble  in  ex- 
cess, but  soluble  in  caustic  alkali. 
White  precipitate. 
White  precipitate. 
No  precipitate. 
White  precipitate. 
Yellow  precipitates. 
Yellow  precipitate. 
Black  precipitates. 


TIN". 


175 


tallic  state,  it  is  separated  from  the  earths,  through  which  it  is 
diffused,  by  a  melting  heat — the  metal  sinking  to  the  bottom 
of  the  crucible,  and  the  earthy  matters  floating  on  the  surface. 
It  is  a  white  metal,  with  a  reddish  hue,  very  crystalline  in 
structure,  volatilizes  at  a  white  heat,  and  burns  in  the  air  with 
a  pale  blue  flame,  forming  oxide  of  bismuth.  The  metal  does 
not  tarnish  by  exposure  to  the  air.  It  combines  with  oxygen 
in  several  proportions,  the  principal  of  which  are:  the  protox- 
ide Bi2  03,  formed  by  combustion,  or  calcination  of  the  sub- 
nitrate,  and  the  bismuthic  acid  Bi2  05.  These  oxides  appear  to 
combine  together  in  several  proportions. 

Sulphate  of  bismuth  may  be  prepared  by  dissolving  the 
oxide  in  concentrated  sulphuric  acid,  and  chloride  of  bismuth  by 
dissolving  in  hydrochloric  acid.  These  salts  are  decomposed 
by  dilution. 

Nitrate  of  Bismuth. — Nitric  acid  dissolves  bismuth  easily, 
forming  the  nitrate,  which  crystallizes  in  beautiful  white  crys- 
tals. This  salt  is  also  decomposed  by  water;  indeed,  all  the 
neutral  salts  of  bismuth  are  precipitated  by  adding  water  to 
their  solutions,  there  being  formed  salts  with  the  oxides. 

The  action  of  reagents  upon  the  solutions  of  bismuth  is  as 
follows : — 


Potash,  soda,  and  ammonia  . 

Carbonates  of  the  alkalies  . 

Yellow  prussiate  of  potash  . 

Eed  prussiate  of  potash  .  . 

Solution  of  galls     .    .    .  . 

Iodide  of  potassium    .    .  . 

Chromates  of  potash    .    .  . 

Sulphurets  of  the  alkalies  . 


.  White  precipitates,  not  soluble 

in  excess. 
.  White  precipitates,  not  soluble 

in  excess. 
.  White  precipitate. 
.  Pale-yellow  precipitate. 
.  Orange-yellow  precipitate. 
.  Brown  precipitate. 
.  Yellow  precipitates. 
.  Black  precipitates. 


Tin  (Sn  59). 

This  metal  has  nearly  the  c*olor  and  lustre  of  silver ;  it  is  one 
of  the  few  metals  which  were  known  to  man  at  a  very  early 
period  of  his  history,  and  was  extensively  used  in  all  countries, 
both  east  and  west,  having  any  pretensions  to  civilization. 
This  was  probably  owing  to  the  ores  of  the  metal  being  easily 
reduced  to  the  metallic  state,  these  being  in  general  oxides ;  so 
that  by  merely  fusing  them  with  carbonaceous  matter,  such  as 
wood  or  coal,  which  combines  with  the  oxygen,  the  metal  is 
fused,  and  sinks  in  the  melted  state  to  the  bottom  of  the  fur- 
nace. 


176 


TIN. 


The  principal  localities  for  obtaining  tin,  are  Cornwall  in 
England,  Bohemia,  Mexico,  and  the  East  Indies  ;  in  the  former 
country,  the  metal  has  been  wrought  for  many  ages,  and  may 
almost  be  said  to  be  the  first  nucleus  of  civilization  in  this 
country,  as  it  formed  the  great  mart  where  the  civilized  and 
commercial  Phoenicians  obtained  the  tin  which  was  so  abun- 
dantly used  by  them.  The  ore  is  found  in  Cornwall  both  in 
veins  traversing  the  primary  rocks,  and  in  small  rounded 
grains  in  the  neighborhood  of  these  rocks,  imbedded  in  what 
geologists  term  the  alluvial  deposit,  signifying  the  deposit 
formed  by  the  washing  away  of  the  fragments  of  the  primary 
rocks  with  water.  This  gives  the  purest  tin,  and  is  distin- 
guished by  the  name  of  stream  tin.  The  ore  obtained  from 
the  veins  is  generally  contaminated  with  other  metals,  such  as 
iron,  copper,  arsenic,  and  the  like,  but  is  partially  purified  by 
roasting,  washing  out  the  decomposed  foreign  substances,  and 
smelting  in  a  kind  of  cupola.  Several  other  operations  of  re- 
fining follow  this,  which  need  not  be  detailed ;  but  there  are 
always  some  few  of  the  impurities  remaining  in  a  portion  of 
the  tin.  That  portion  which  contains  these  impurities  is  termed 
block  tin.  The  pure  grain  tin  is  heated  till  it  becomes  brittle, 
and  is  then  let  fall  from  a  height,  which  splits  it  into  small  bars 
or  prisms,  and  in  this  state  it  is  found  in  commerce.  These 
bars,  in  bending,  make  a  peculiar  crackling  noise,  and  become 
heated ;  phenomena  probably  owing  to  the  separating  of  their 
parts,  and  the  sudden  fracture  caused  by  bending. 

Tin  is  very  extensively  used  in  dyeing  and  printing  both 
cotton  and  woollen.  Its  introduction  as  a  mordant  may  be  con- 
sidered as  forming  an  era  in  the  art  of  dyeing,  and,  like  many 
other  important  improvements  in  this  art,  was  the  result  of  ac- 
cident, an  account  of  which  is  given  by  Berthollet  as  follows  : 
"  A  little  while  after  the  cochineal  became  known  in  Europe, 
the  scarlet  process  by  means  of  the  solution  of  tin  was  disco- 
vered. It  is  stated  that  about  the  year  1630,  Cornelius  Dreb- 
bel  observed,  by  .an  accidental  mixture,  the  brilliancy  which 
the  solution  of  tin  gave  to  the  infusion  of  cochineal.  He  com- 
municated his  observation  to  his  son-in-law,  Kuffelar,  who  was 
a  dyer  at  Leyden.  He  soon  improved  the  process,  kept  It  a 
secret  in  his  work  shop,  and  brought  into  vogue  the  color  which 
bore  his  name." 

Soon  afterwards,  a  German  chemist  found  out  the  process  of 
dyeing  scarlet  by  means  of  the  solution  of  tin.  He  brought 
his  secret  to  London  in  1643  ;  it  became  known  to  others,  was 
soon  afterwards  diffused  over  Europe,  and  its  applications  be- 
came more  extended,  as,  whenever  a  new  dye-drug  was  intro- 


PROTOCHLORIDE  OF  TIN. 


177 


ducecl  into  the  art,  the  solution  of  tin  was  universally  applied, 
by  which  means  it  became  a  standard  mordant  for  the  various 
dyewoods,  such  as  logwood,  Brazil-wood,  and  the  like. 

Copper  boilers,  used  for  dyeing  woollens  and  silks,  have  gene- 
rally a  part  covered  jvith  or  made  of  tin,  which  is  intended  to 
prevent  the  acid  mordant  from  acting  upon  the  copper,  and 
this  it  does  by  a  galvanic  action,  the  tin  being  slowly  acted 
upon,  while  the  copper  is  protected. 

Tin  combines  with  oxygen  in  three  different  proportions  : — 

Protoxide  Sn  O. 

Sesquioxide  Sn2  03  =  Sn  0,  Sn  02. 

Peroxide  So  02. 

There  are  salts  of  tin  corresponding  to  these  oxides,  all  more 
or  less  useful  in  dyeing. 

Protoxide  of  Tin  is  formed  by  precipitation  from  a  solu- 
tion of  the  protochloride  of  tin  by  carbonate  of  potash  or  soda. 
It  is  obtained  as  a  white  powder,  wh^ch  is  a  hydrate  of  the 
oxide,  and  which,  if  heated  to  176°,  loses  its  water  of  combina- 
tion, and  becomes  black,  and  may  be  kept  in  this  state;  but 
if  brought  to  a  red  heat,  or  into  contact  with  a  redhot  body,  it 
takes  fire,  and  in  burning  passes  into  the  state  of  peroxide. 
The  white  hydrated  oxide  is  easily  dissolved  in  acids,  and  also 
in  solutions  of  the  alkalies,  but  these  alkaline  solutions  are  not 
permanent ;  for  if  diluted  with  water,  a  portion  of  the  tin  is 
precipitated,  and  another  portion  passes  into  the  state  of  per- 
oxide. Also,  when  brought  into  contact  with  other  oxides 
which  yield  their  oxygen  freely,  such  as  peroxide  of  iron,  a 
reaction  takes  place  ;  the  iron  is  reduced  to  a  lower  state  of 
oxidation,  and  the  tin  is  raised  to  a  higher.  These  reactions 
and  properties  are  taken  advantage  of  in  many  of  the  opera- 
tions in  dyeing. 

The  protoxide  of  tin  and  its  protosalts  all  come  under  the 
denomination  of  stannous  salts;  and  it  may  be  remarked  of 
them,  as  a  general  characteristic,  that  they  all  absorb  oxygen 
from  the  air  by  exposure. 

Protochloride  of  Tin  (Salts  of  Tin). — This  salt  is  pre- 
pared by  dissolving  tin  in  strong  hydrochloric  acid,  with  the 
assistance  of  heat,  the  solution  evaporating  and  crystallizing  in 
the  ordinary  way.  The  crystals  were  formerly  said  to  contain 
three  proportions  of  water,  about  22  per  cent.;  but  according 
to  a  recent  investigation  by  Dr.  Penney,  they  contain  only  two 
proportions.  The  crystals  dissolve  in  a  small  portion  of  water; 
but  if  put  into  a  large  quantity,  the  whole  becomes  milky,  and 
a  white  powder  separates,  which  is  an  oxychloride  of  tin.  A 
complete  and  clear  solution  of  salts  of  tin  in  water  cannot  be 
,12 


178 


DEUTOXIDE  OR  SESQUIOXIDE  OF  TIN. 


retained  for  any  length  of  time  on  account  of  the  great  attrac- 
tion which  this  salt  has  for  oxygen.  A  little  hydrochloric  acid 
put  into  the  water,  however,  has  the  effect  of  greatly  retarding, 
and,  indeed,  of  almost  wholly  preventing  this  decomposition. 
In  establishments  where  the  dyers  prepare  their  own  salts  of  tin, 
they  do  not  crystallize  it,  and  as  there  is  nearly  always  an  ex- 
cess of  acid,  some  of  the  phenomena  mentioned  may  not  have 
been  observed. 

On  adding  potash  to  salts  of  protochloride  of  tin,  a  double 
salt  is  formed  of  chloride  of  tin  and  chloride  of  potassium, 
which  may  be  crystallized. 

Protosulphate  of  Tin. — Sulphuric  acid  dissolves  tin 
slowly,  and  forms  a  thin,  pasty-looking  mass,  which,  by  evapo- 
ration, yields  crystals.  This  salt  is  not  used  in  the  dye-house  ; 
it  is,  indeed,  immediately  decomposed  by  aqueous  dilution. 

Protonitrate  of  Tin. — Protoxide  of  tin  dissolves  easily  in 
dilute  nitric  acid,  but  it  cannot  be  concentrated,  from  its  liability 
to  pass  into  the  state  of^peroxide.  When  nitric  acid  of  specific 
gravity  1.114  =  23  of  Twaddell,  is  poured  upon  the  metal,  it 
dissolves  it  rapidly,  and  much  heat  is  evolved,  which  ought 
to  be  kept  down  by  placing  the  vessel  containing  the  acid  in 
cold  water.  If  this  be  properly  done,  a  protonitrate  of  tin  is 
formed,  the  action  being 

Nitric  acid    ^  Hydrogen  gas. 

Tin  ...  .      Sn..    — -Nitrate  of  tin. 

But  should  the  heat  be  allowed  to  rise  too  high,  the  nitric  acid 
is  also  decomposed,  and  the  tin  passes  into  a  higher  state  of 
oxidation.  Also,  if  the  action  is  very  rapid,  ammonia  is  formed 
between  the  hydrogen  and  nitrogen,  and  consequently  a  double 
salt  of  tin  and  ammonia;  but  the  greater  proportion  of  the  tin 
is  precipitated  as  a  white  pasty  mass  of  peroxide. 

Tartrate  of  Potash  and  Tin  is  prepared  by  dissolving 
protoxide  of  tin  in  bitartrate  of  potash  (tartar  or  cream  of  tar- 
tar). This  forms  a  very  soluble  salt,  occasionally  used  in  dye- 
ing woollens;  but  in  this  case  the  tartar  is  added  to  the  salts 
of  tin. 

A  combination  of  the  protoxide  of  tin,  arsenic,  and  soda,  has 
been  patented  as  a  salt  in  calico-printing,  under  the  name  of 
Stanno-Arsenite  of  Soda. 

Deutoxide,  or  Sesquioxide  of  TiN=Sn2  03,  can  be  pre- 
pared by  adding  to  a  saturated  solution  of  protochloride  of  tin 
some  newly-precipitated  peroxide  of  iron;  a  double  decomposi- 
tion takes  place  as  follows : — 


PEROXIDE  OF  TIN. 


179 


2  proportions  proto-  (2  CI 


chloride  of  tin      (2  Sn 
1  proportion  of  per-  f  2  Fe. 
oxide  of  iron      "^3  0.. 


2  Protochloride  of  iron  in 
solution. 


Sesqnioxide  of  tin  preci- 
pitated. 


Strong  hydrochloric  acid  dissolves  this  oxide,  and  forms  with 
it  a  sesquichloride,  thus: — 


The  other  salts  corresponding  to  this  oxide  have  not  been 
examined;  but  the  distinctive  character  of  the  oxide  itself  may 
be  made  evident  by  the  two  following  reactions  :  Ammonia 
dissolves  this  oxide,  but  does  not  dissolve  the  protoxide ;  and 
hydrochloric  acid  dissolves  this  oxide,  but  does  not  dissolve  the 
peroxide.  There  can  be  little  doubt  but  that  an  investigation 
into  the  sesquioxide  and  its  salts  would  explain  many  of  the 
hitherto  unexplained  phenomena  of  dyeing;  -and  that  it  is  highly 
probable  that  the  formation  of  salts  of  this  class  plays  a  con- 
siderable part  in  many  dyeing  operations ;  such  as  those  pro- 
cesses in  which  chloride  of  tin  is  mixed  with  pernitrate  of  iron, 
as  for  royal  blues,  &c. 

Peroxide  of  Tin. — The  ores  of  tin,  termed  tinstone,  are 
mostly  peroxide.  They  are  black,  shading  to  brown  ;  in  this 
state,  the  oxide  is  not  soluble  in  acids,  but  becomes  so  by  pre- 
vious ignition  with  an  alkali. 

When  metallic  tin  is  put  into  dilute  nitric  acid,  and  the  action 
allowed  to  proceed  rapidly,  or  when  heat  is  applied,  there  is 
formed  a  hydrated  peroxide,  as  a  white  mass,  which  contains 
11  proportions  of  water.  Dilute  hydrochloric  acid  dissolves 
this  oxide  slightly,  but  it  is  not  soluble  in  nitric  or  sulphuric 
acids.  If  acted  upon  by  hydrochloric  acid,  and  allowed  to 
stand  for  some  time,  and  the  supernatant  liquor  then  poured 
off,  the  remaining  insoluble  oxide  is  soluble  in  water.  If  this 
hydrated  peroxide  be  dried  with  heat,  it  loses  its  water,  and 
passes  into  the  same  state  as  the  ore.  Boiling  water,  poured 
upon  it,  will  effect  similar  changes. 

The  peroxide  of  tin  is  obtained  easily  by  precipitation  from 
a  solution  of  bichloride,  by  adding  an  alkaline  carbonate. 
Thus  prepared,  and  in  this  condition,  the  peroxide  is  easily  dis- 
solved in  hydrochloric  acid,  either  strong  or  dilute;  but  if 
this  oxide  be  heated  in  any  way,  as  by  pouring  boiling  water 
upon  it,  strong  hydrochloric  acid  will  not  dissolve  it,  and  dilute 
acid  only  partially.    The  oxide  has  now  indeed  every  property 


1  Sesquioxide  of  tin  | 
3  Hydrochloric  acid  | 


3  Water. 


1  Sesquichloride  of  tin. 


180 


PERCHLORIDE  OF  TIN. 


that  it  has  when  formed  by  the  nitric  acid  process.  It  is  also 
soluble  in  pure  water,  after  being  made  into  a  paste  with 
strong  hydrochloric  acid,  but  the  addition  of  a  little  of  this 
acid  to  the  watery  solution  will  precipitate  it. 

The  changes  effected  upon  this  oxide  by  heat  or  applying 
boiling  water,  are  supposed  to  be  owing  to  its  state  of  hydra- 
tion; but  be  that  as  it  may,  these  peculiarities  ought  to  attract 
the  attention  of  the  practical  dyer;  as  the  annoyances  to  which 
they  give  rise  are  very  considerable,  and  only  require  the 
exercise  of  a  little  care  to  be  avoided.  The  hydrated  peroxide 
of  tin  is  very  soluble  in  caustic  alkalies. 

The  peroxide  of  tin  has  been  termed  stannic  oxide  and  stan- 
nic acid,  as  it  has  certain  acid  properties.  It  combines  with 
alkalies,  and  forms  salts.  y 

Perchloride  of  Tin  {Per muriate  of  Tin). — When  tin  is  dis- 
solved in  a  mixture  of  hydrochloric  and  nitric  acids,  the  salt 
formed  is  generally  the  perchloride  =  Sn  Cl2,  and  is  conse- 
quently that  most  generally  used  in  the  dye-house,  where 
almost  all  salts  are  prepared  by  a  mixture  of  the  acids.  But 
from  what  has  been  stated  in  reference  to  the  separate  oxides 
and  salts,  it  will  be  evident  that  this  subject  stands  in  need  of 
farther  investigation ;  the  modes  of  preparation  are  so  varied 
in  the  proportions  of  each  acid,  in  the  qualities  of  tin  used,  and 
in  the  manner  of  adding  the  tin ;  all  and  each  of  these  circum- 
stances, it  will  be  observed,  make  a  difference.  If  tin  is  added 
too  rapidly,  the  action  and  heat  may  be  so  violent  as  to  pre- 
cipitate some  of  the  oxide  in  an  insoluble  state;  if  added  too 
slowly,and  at  a  temperature  too  low, there  may  be  protochlorides 
formed,  or  mixtures  of  the  different  salts,  in  very  varied  pro- 
portions; and  hence  the  cause  of  the  irregularity  both  in 
quality  and  kind  of  color  produced  by  tin  mordants.  Per- 
chloride of  tin  is  generally  formed  by  dissolving  crystals  of 
the  protochloride  in  a  small  portion  of  water,  adding  nitric 
acid,  and  applying  heat,  or  by  passing  a  steam  of  chlorine  gas 
through  a  solution  of  salts  of  tin.  These  are  termed  in  the 
dye-house  oxychlorides  of  tin. 

Dr.  Penney,  in  a  recent  communication  to  the  Chemical 
Society,  has  recommended  a  simple  means  of  testing  the  quan- 
tity of  tin  present  in  a  solution  of  salt  in  the  proto-state,  founded 
upon  the  reduction  of  chromic  acid  to  oxide  of  chromium,  by 
protoxide  of  tin.  The  method  recommended  for  salts  of  tin  is 
the  following:  100  grains  of  the  crystals  are  put  into  a  vessel 
with  20  oz.  of  water,  and  half  an  ounce  of  hydrochloric  acid  ; 
83 J-  grains  bichromate  of  potash  are  dissolved  in  warm  water, 
and  placed  in  an  alkalimeter,  the  whole  measuring  100  gradua- 
tions; this  solution  is  added  by  degrees  to  the  solution  of  tin, 


SPIRITS  OF  TIN". 


181 


which  takes  a  rich  green  color.  The  solution  of  chrome  is 
added,  until  a  drop  taken  out  and  put  upon  a  drop  of  acetate 
of  lead,  on  a  glass  or  paper  surface,  gives  yellow.  If  the  tin 
solution  is  more  dilute,  and  put  into  a  large  glass  jar,  the  green 
tint,  whenever  the  chrome  is  in  excess,  is  perceptibly  yellow. 
A  little  experience  renders  the  operation  simple.  The  quantity 
of  bichromate  (83J  grains)  is«  equal  to  100  grains  of  pure 
metallic  tin;  hence  every  graduation  of  the  chrome  solution 
taken  to  effect  the  change  described,  is  equal  Jbo  one  grain  of 
tin.  As  83  J  grains  of  bichromate  of  potash  may  not  be  soluble 
in  one  measure  of  the  common  alkalimeter,  two  measures  may 
be  taken;  in  that  case,  two  graduations  will  indicate  one  grain 
of  tin  in  the  salt  tested. 

Solutions  of  tin,  such  as  are  sold  to  calico-printers  under 
/the  term  single  and  double  muriates,  may  be  tested  by  taking  a 
measured  quantity  of  the  solution  and  treating  it  in  the  same 
manner.  Or,  as  recommended  by  Dr.  Penney,  by  taking  a 
weighed  quantity  of  the  solution  of  tin,  say  500  grains,  and 
making  up  with  water  to  fill  the  alkalimeter  ;  then  dissolve 
41.6  grains  of  bichromate  of  potash  in  warm  water,  and  add 
the  solution  of  tin  to  this  very  cautiously,  as  long  as  the  tint 
remains  of  an  olive-green  color,  or  until  a  drop  taken  out  and 
added  to  a  drop  of  lead  in  solution  gives  a  yellow  color. 
Whenever  the  yellow  ceases  to  be  obtained,  the  operation  is 
complete.  Finally,  by  dividing  1000  by  the  number  of  gradua- 
tions taken  of  the  tin  solution,  the  percentage  of  the  tin  is 
ascertained.  Thus,  say  that  41.6  of  bichromate  of  potash  re- 
quired 38  graduations  of  tin  solution  to  reduce  the  chromic 
acid,  then 

38)1000(26.3  =  percentage  of  tin  in  solution.* 

This  test  only  applies  to  tin  in  solution  in  the  proto-state, 
but  gives  no  change  in  the  persalts  of  tin,  and  is  therefore  not 
applicable  to  many  of  the  spirits  used  in  the  dye-house. 

Spirits. — The  solutions  of  tin,  in  the  technical  language  of 
the  dye-house,  are  termed  spirits,  with  an  affix  to  each  mode  of 
preparation,  to  denote  their  special  application,  such  as  red 
spirits,  yellow  spirits,  plumb  spirits,  &c.  The  preparation  of 
these  spirits  is  a  matter  of  much  pride  amongst  dyers,  and  each 
has  some  little  peculiarity  which  he  keeps  to  himself,  and  on 
the  virtue  of  which  he  supposes  all  his  success  depends.  These 
peculiarities  are  generally  in  the  proportion  of  the  acids  and 
the  tin,  and  the  manner  of  mixing  them.  However,  as  may  be 
supposed,  they  are  not  equally  answerable  for  all  the  purposes 

*  Journal  of  Chemical  Society,  for  1851. 


182 


SPIRITS  OF  TIN. 


to  which  they  are  applied;  hence  the  reason  that  we  find  one 
dyer  best  at  reds,  another  at  purples,  another  at  blacks,  and 
another  at  browns. 

We  will  here  give  a  few  practical  methods  of  preparing  these 
several  spirits,  reserving  our  remarks  upon  their  varieties  and 
effects  to  our  general  observations  on  mordants,  to  which  we 
will  devote  a  separate  chapter,  in  order  that  we  may  be  able  to 
go  fully  into  the  subject. 

The  first  process  in  preparing  spirits  is,  to  feather  the  tin. 
This  is  done  by  melting  it  in  an  iron  ladle,  and  pouring  it,  when 
in  a  melted  state,  into  a  vessel  filled  with  cold  water,  the 
hand  to  be  held  as  high  as  possible,  so  that  it  may  pour  more 
in  drops.  The  appearance  of  the  tin  in  this  state  is  beyond 
description  beautiful.  By  this  process  of  feathering,  a  very 
extended  surface  of  metal  is  exposed  to  the  acid,  which  facili- 
tates its  solution  very  much. 

Eed  Spirits. — If  red  spirits  be  wanted,  that  is,  a  mordant  for 
dyeing  red  upon  cotton  by  Brazil-wood,  the  general  method  is 
to  take  three  measures  of  muriatic  acid,  and  one  of  nitric  acid, 
then  add  the  tin  by  degrees  to  this  mixture  so  long  as  the  acids 
continue  to  dissolve  the  metal ;  care  ought  to  be  taken  not  to 
add  it  too  rapidly,  but  bit  by  bit,  adding  one  piece  just  as  the 
other  is  dissolved.  We  know  that  this  is  not  generally 
attended  to,  as  one  handful  of  the  metal  is  put  in  after  another, 
at  certain  and  too  often  irregular  intervals  of  time,  giving  very 
annoying  results.  When  the  metal  is  put  in  too  rapidly,  or 
too  much  at  once,  the  action  becomes  violent,  the  solution  gets 
heated,  the  nitric  acid  is  decomposed,  ammonia  is  formed  in  the 
solution,  and,  when  the  solution  cools,  a  quantity  of  peroxidized 
tin  falls  to  the  bottomas  a  gelatinous  precipitate,  creating  much 
loss.  When  spirits  thus  prepared  are  used  for  a  brilliant  red 
upon  cotton  by  Brazil-wood,  the  proper  hue  is  never  obtained, 
the  color  being  always  more  or  less  brownish.  The  propor- 
tions of  the  acids  for  preparing  the  red  spirits  are  not  invariably 
three  to  one ;  the  mixture  varies  from  half  and  half  to  five  to 
one,  depending  upon  the  taste  and  experience  of  the  dyer. 
Some  dyers  only  dissolve  a  given  quantity  of  the  metal  to  the 
pound  weight  of  the  mixed  acids,  varying  from  one  and  a  half 
to  three  ounces  to  the  pound ;  but  according  to  our  experience, 
the  acids,  in  whatever  proportions  they  are  mixed,  ought  to  be 
saturated,  at  least  so  far  as  they  will  become  saturated,  observ- 
ing the  precautions  described  above.  We  have  also  found  that 
when  much  nitric  acid  is  used,  the  reds  are  generally  deeper  in 
color,  and  have  a  very  great  tendency  to  turn  brown,  especially 
if  the  goods  be  dried  by  heat;  but  when  the  muriatic  acid  pre- 


OXALATE  OF  TIN. 


183 


vails,  the  color  obtained  has  more  of  the  crimson  or  rose  tint, 
and  is  not  so  liable  to  become  brown  in  drying. 

Plumb  Spirits.— This  solution  is  prepared  by  dissolving  tin 
in  hydrochloric  acid,  diluted  with  about  a  seventh  of  water, 
adding  two  ounces  of  tin  to  every  pound  weight  of  acid.  The 
tin,  as  in  other  cases,  ought  to  be  added  gradually.  Some, 
however,  add  nitric  acid,  and  prefer  it  thus  mixed,  and  others 
add  as  much  tin  as  the  acid  will  dissolve  when  cold. 

Barwood  Spirits. — The  method  given  for  the  preparation 
of  this  solution  is  six  measures  muriatic  and  one  of  nitric  acid, 
adding  tin  gradually  until  white  bubbles  begin  to  rise  to  the 
surface,  allowing  the  solution  to  stand  for  twelve  hours  before 
using  it,  a  rather  uncertain  test  of  quantity  of  tin,  and  of  the 
quality  of  the  spirits. 

Yellow  Spirits.— This  solution  is  now  seldom  used  ;  it  was 
applied  as  a  mordant  for  the  dyeing  of  yellow  by  quercitron 
bark,  and  was  merely  the  substitution  of  sulphuric  acid  for 
the  nitric  acid  of  the  common  red  spirits.  It  was  proposed  by 
Dr.  Bancroft  as  a  question  of  cheapness  in  the  preparation  of 
scarlet  spirits,  and  was  afterwards  much  used,  as  stated,  for 
dyeing  yellows,  as  its  name  implies.  By  this  method  of  pre- 
paration, the  tin  was  generally  in  the  proto-state,  which  gave  it 
a  peculiarity  in  relation  to  the  common  red  spirits,  as  it  afforded 
bluer  tints  with  red  woods  when  used  as  a  raising  or  alterant. 
The  tin  spirits,  as  double  and  single  muriates,  the  salts  of  tin 
dissolved  in  water  and  muriatic  acid,  and  the  metallic  tin  dis- 
solved in  hydrochloric  acid  {plumb  spirits),  all  have  the  same 
effect.  Some  dyers,  however,  use  the  red  spirits  for  alterants 
and  dyeing  yellows. 

Instead  of  using  hydrochloric  acid  for  preparing  spirits,  many 
woollen  dyers  use  sal-ammoniac  or  common  salt,  adding  it  to 
nitric  acid  in  the  proportion  of  6  lbs.  nitric  acid  to  1  of  water 
in  which  1  lb.  sal-ammoniac  is  dissolved,  and  then  adding  10 
oz.  of  tin. 

Acetate  of  Tin  is  prepared  by  adding  a  solution  of  acetate 
of  soda  to  protochloride  of  tin ;  common  salt  is  formed  and 
acetate  of  tin;  the  former  is  not  hurtful  to  the  dyer. 

Oxalate  of  Tin  may  be  formed  in  the  same  way,  by  using 
oxalate  of  soda,  or  by  dissolving  precipitated  protoxide  of  tin 
in  oxalic  acid. 

In  dissolving  tin  in  hydrochloric  acid,  it  is  often  observed 
that  towards  the  end  of  the  process,  when  the  tin  is  in  the  solu- 
tion, parts  of  the  metal  seem  to  dissolve,  while  other  parts 
become  coated  with  a  crystalline  substance,  soluble  only  with 
much  difficulty,  and  occasioning  both  annoyance  and  loss. 
This  is  caused  by  one  portion  of  the  solution  becoming  denser 


184 


TITANIUM. 


than  other  portions,  a  galvanic  action  being  induced  between, 
those  parts  of  the  tin  in  the  weaker  portion  of  the  solution, 
and  the  parts  in  the  stronger,  consequently  depositing  the  tin 
upon  the  metal  in  the  strongest  parts  of  the  solution.  This 
evil  can  be  prevented  by  occasionally  stirring  the  solution. 

The  following  is  the  reaction  of  solutions  of  other  substances 
on  the  protosalts  of  tin  : — 

Potash  and  soda  .    .    .    White  precipitates,  soluble  in  excess. 

Ammonia   ditto,         insoluble  in  excess. 

Carbonates  of  the  alkalies        ditto,  soluble  in  caustic  alkali. 
Yellow  prussiateof  potash,  White  precipitate. 
Red  prussiate  of  potash,  ditto. 
Galls  in  solution  .    .    .     Slight  yellow  precipitate. 
Chloride  of  gold  .    .    .     Deep  purple  precipitate  (purple  of 

Cassius). 

Sulphurets  of  alkalies  .     Brown  precipitates. 
With  the  persalts  of  tin  : — 

Potash  and  soda  .    .    .      White  precipitates,  soluble  in  excess. 

Ammonia   ditto,  ditto. 

Carbonates  of  the  alkalies  ditto,  soluble  in  caustic  alkali. 
Yellow  prussiate  of  potash  No  precipitate. 
Red  prussiate  of  potash  ditto. 
Solution  of  galls     .    .  ditto. 

Sulphurets  of  the  alkalies  Yellow  precipitates,  soluble  in  caus- 
tic potash. 


Titanium  (Ti  25). 

This  metal  was  discovered  in  1791.  It  is  generally  found  in 
nature  in  combination  with  iron;  a  great  number,  indeed,  of 
the  iron  ores  of  this  country  seem  to  contain  traces  of  this 
metal.  It  regularly  makes  its  appearance  in  the  blast-furnace, 
combined  with  cyanogen  and  nitrogen,  in  the  form  of  copper 
colored  cubes.  Titanic  acid  is  soluble  in  concentrated  muriatic, 
and  better  still,  sulphuric  acid,  but  becomes  precipitated  by 
diluting  and  boiling  the  solution.  It  combines  in  three  propor- 
tions with  oxygen,  forming:  — 

Protoxide  =Ti  0. 

Sesquioxide    .  =  Ti203 

Peroxide  =Ti  02. 

The  latter  oxide,  on  account  of  its  combining  with  the  alkalies, 
and  forming  soluble  salts  with  them,  has  been  termed  titanic 
acid. 


CHROMIUM. 

The  salts  formed  by  the  action  of  acids  upon  this  metal  "have 
not  been  much  studied;  those  which  have  been  investigated' 
most  carefully  are  the  salts  formed  by  the  peroxide  or  titanic 
acid.  Solutions  of  these  salts  give  a  brown  precipitate  with 
galls ;  but  all  the  compounds  of  this  metal  are  very  intractable, 
and  being  besides  very  scarce,  they  are  of  little  use  in  the  arts. 


Chromium  (Or  26.2). 

This  metal  is  found  in  considerable  quantities  in  nature, 
combined  with  lead  and  iron.  The  latter  (chrome  iron)  is  its 
principal  ore.  It  is  found  in  America  and  in  different  parts  of 
the  Continent  of  Europe;  also  in  Shetland,  and  in  Fifeshire  in 
Scotland.    The  composition  of  the  ore  is  Fe  0  +  Cr203. 

The  metal  was  discovered  in  1797  by  Vauquelin.  It  ap- 
proaches to  cast-iron  in  appearance,  but  has  only  been  obtained 
in  the  state  of  powder.  It  is  very  difficult  to  fuse,  and  does 
not  undergo  oxidation  by  exposure  to  the  air.  The  metal  is 
not  acted  upon  directly  by  the  common  acids;  but  may  be  ob- 
tained in  combination  with  acids,  by  decomposing  some  of  its 
salts  or  oxides,  of  which  there  are  two,  namely — 

Peroxide  Cr203. 

#         Chromic  acid  Cr  03. 

The  last  (chromic  acid)  forms  the  acid  of  the  salts  named  chro- 
mates.  The  oxide  of  chromium  exists  combined  with  iron  in 
the  ore,  as  stated  above ;  it  is  not,  however,  obtained  from  the 
ore,  but  by  acting  upon  some  of  the  salts  of  chromic  acid.  It 
is  of  a  beautiful  green  color,  and  may  be  prepared  by  various 
methods ;  e.  g.  take 

1  part  bichromate  of  potash, 

1J  part  sal-ammoniac, 

1  part  carbonate  of  potash, 

and  ignite  this  mixture  in  a  crucible;  the  chromic  acid  is  de- 
composed, and  the  oxide  formed.  By  digesting  what  remains 
in  water,  the  oxide  is  obtained  as  an  insoluble  powder.  An- 
other and  more  easily-practised  method  for  the  dye-house,  is 
that  adopted  on  the  Continent,  and  is  as  follows:  Take  9  lbs. 
of  bichromate,  of  potash,  and  dissolve  in  5  gallons  of  boiling 
water;  then,  into  a  boiler  containing  23  gallons  of  boiling 
water,  put  10  lbs.  of  the  white  oxide  of  arsenic;  boil  for  ten 
minutes,  and  allow  the  liquor  to  settle.  The  clear  is  then 
mixed  with  the  solution  of  bichromate  of  potash,  stirring  all 
the  time,  when  very  soon  the  hydrated  oxide  of  chrome  is 


186 


SULPHATE  OF  CHROMIUM. 


formed  and  precipitated.  After  the  whole  is  cool,  it  is  put 
upon  a  filter,  and  the  oxide  which  remains  upon  the  filter  is 
washed  with  boiling  water.  If  a  little  hydrochloric  acid  be 
added,  the  chrome  oxide  is  obtained  as  a  green  solution.  This 
oxide  has  long  been  used  to  give  a  green  color  to  glass  and 
porcelain,  and  has  lately  been  introduced  and  is  now  exten- 
sively used  in  calico  printing.  It  is  also  partially  used  in  the 
dye-house  for  dyeing  colors  of  various  tints,  all  of  which  have 
the  valuable  property  of  permanency. 

Chloride  of  Chromium. — The  oxide  of  chromium  dissolves 
readily  in  hydrochloric  acid,  and  forms  a  chloride,  which  has  a 
deep  green  color  and  a  strong  acid  reaction.  Evaporated  nearly 
to  dryness,  there  are  produced  red-colored  scales,  which  give  a 
green  solution  with  water.  The  following  method  for  the  pre- 
paration of  the  chloride  has  been  recommended  :  Hydrochloric 
acid  is  diluted  with  water  until  the  acid  no  longer  gives  off 
fumes;  it  is  then  heated,  and,  when  hot,  as  much  of  the  oxide 
of  chromium,  prepared  by  the  arsenic  solution,  is  added  as  the 
acid  will  dissolve :  the  whole  is  then  left  to  settle,  and  the  clear 
is  taken  off.  This  contains  some  free  acid,  which  would  act 
upon  the  cotton  fibre ;  to  remove  it,  and  obtain  the  salt  in  a 
neutral  state,  potash  lye  is  poured  in  gradually,*  until  the  oxide 
of  chromium  begins  to  be  precipitated.  The  solution  thus 
prepared  has  a  dark-green  color,  and  is  used  for  several  opera- 
tions in  dyeing.  Preparations  of  this  salt,  or  rather  mixture 
of  salts,  have  been  long  used  in  calico  printing.  These  are 
made  by  mixing  together  chromate  of  potash,  hydrochloric 
acid,  and  tartaric  acid,  in  a  great  variety  of  proportions,  giving 
green  tints  of  various  depths,  according  to  the  mixture  used. 

Sulphate  of  Chromium. — Sulphuric  acid  added  to  oxide 
of  chromium  dissolves  it,  and  forms  a  green-colored  solution, 
which  does  not  crystallize.  If  evaporated  to  dryness,  it  loses 
its  solubility  in  water;  but  by  adding  sulphate  of  potash  or  a 
solution  of  potash,  taking  care  not  to  precipitate  any  of  the 
oxide,  there  is  formed  a  double  salt,  termed  chrome  alum.  The 
solution  of  this  double  salt  is  a  bluish-purple;  it  crystallizes 
easily,  giving  dark  purple  colored  crystals;  but  care  must  be 
taken  that  the  solution  is  not  heated  to  the  boiling  point,  as  it 
is  thereby  turned  green,  and  yields  no  crystals. 

Oxalate,  acetate,  tartrate,  &c,  of  chromium,  may  be  ob- 
tained by  dissolving  the  oxide  in  any  of  these  acids;  they  all 
give  green  colored  solutions.  If  we  mix  together  one  part  of 
bichromate  of  potash,  two  of  crystallized  oxalic  acid,  and  two 
of  binoxalate  of  potash,  and  dissolve  the  mixture  in  boiling 
water,  a  salt  is  formed,  which  crystallizes  in  nearly  black-co- 
lored crystals.    It  is  a  double-oxalate  of  chromium  and  potash. 


CHROMIC  ACID. 


187 


Chromic  Acid. — Salts  of  this  acid  are  prepared  directly 
from  the  chrome  iron  ore;  and  the  acid  is  obtained  by  de- 
composing these  salts.  Chromic  acid  is  of  a  beautiful  deep 
orange  color,  approaching  to  scarlet,  and  may  be  obtained  in  a 
crystalline  form.  Various  methods  have  been  proposed  for 
preparing  it;  the  following,  by  Mr.  Robert  Warrington,  is 
probably  the  most  simple:  "Take  100  measures  of  a  cold 
saturated  solution  of  bichromate  of  potash  (prepared  by  boil- 
ing, and  then  allowing  the  solution  to  cool,  and  deposit  the  ex- 
cess of  the  salt),  and  add  to  this  from  120  to  150  measures  of 
concentrated  sulphuric  acid;  the  latter  should  be  free  from 
sulphate  of  lead,  as  otherwise  it  would  fall  as  chromate  and 
sulphate  of  lead  with  the  chromic  acid  on  dilution  with  the 
bichromate.  The  mixture  is  then  allowed  to  cool,  and  the 
chromic  acid  gradually  crystallizes  in  beautiful  dark  crimson 
needles.  Decant  the  fluid  part,  and  place  the  crystals  with  the 
adhering  sulphuric  acid  on  a  thick  flat  tile  of  biscuit  porcelain  ; 
another  tile  is  then  to  be  placed  upon  the  crystals,  and  the 
whole  submitted  to  a  pressure  for  a  considerable  time.  On  re- 
moving the  chromic  acid,  it  will  be  found  in  a  perfectly  dry 
state,  and  yielding  a  mere  trace  of  sulphuric  acid  on  examina- 
tion."* 

Chromic  acid  may  also  be  prepared  from  the  chromate  of  lead, 
which  results  from  the  mixture  of  a  salt  of  lead  and  bichromate 
of  potash  at  the  bottom  of  the  chrome  tubs  used  in  dj^eing 
yellows.  Two  parts  of  strong  sulphuric  acid  being  added  to 
one  part  of  dry  chromate  of  lead  slightly  heated,  and  allowed 
to  stand  for  about  twelve  hours,  water  is  then  added,  when  the 
lead  is  precipitated  as  a  sulphate,  and  the  chromic  acid,  mixed 
with  a  little  sulphuric  acid,  remains  in  solution.  The  liquid  is 
decanted  and  evaporated  at  a  boiling  heat;  on  cooling,  the 
greater  portion  of  the  chromic  acid  separates  in  beautiful  car- 
mine-red crystals.  If  the  process  be  carefully  conducted,  a 
great  portion  of  what  is  now  little  better  than  thrown  away, 
might  be  made  useful  by  a  trifling  addition  of  expense. 
Another  method  of  preventing  waste  is  to  add  potash  to  the 
solution,  so  as  to  form  chromate  and  sulphate  of  potash,  which 
may  afterwards  be  separated  by  crystallization. 

Chromic  acid  combines  with  the  different  bases,  and  forms 
a  series  of  important  salts.  With  potash  it  combines  in  two 
proportions,  forming  what  is  termed  the  yellow  and  the  red 
chromate  of  potash.  The  yellow  chromate  of  potash  may  be 
prepared  by  adding  to  two  pounds  of  red  chromate  one  pound 
of  caustic  potash ;  it  crystallizes  in  small  crystals  of  a  rich 

*  Proceedings  of  the  Chemical  Society,  vol.  i. 


183 


BICHROMATE  OF  POTASH. 


deep  lemon  color,  composed  of  one  proportion  of  acid  and  one 
of  potash.    This  salt  is  not  much  used  in  the  arts. 

Bichromate  (Red  Chromate)  of  Potash. — This  salt  may- 
be prepared  from  the  yellow  chromate  by  adding  a  little  sul- 
phuric acid,  which  combines  with  a  portion  of  the  potash, 
leaving  two  proportions  of  chromic  acid  in  union  with  one  pro- 
portion of  potash  which  crystallizes  in  large  square  tabular 
crystals  of  a  rich  orange-red  color.  This  is  the  salt  used  in 
the  arts,  not  only  for  dyeing,  but  for  the  preparation  of  other 
chrome  compounds,  and  is  prepared  on  the  large  scale  in  the 
following  manner:  Chrome  iron  ore,  after  being  finely  ground 
and  sifted,  is  mixed  with  a  quantity  of  dried  nitrate  and  car- 
bonate of  potash.  This  mixture  is  thrown  into  a  reverberating 
furnace,  and  subjected  to  a  powerful  heat,  being  occasionally 
stirred.  When  perfectly  calcined,  the  mass  is  raked  out  and 
dissolved  in  water.  It  is  then  boiled  for  several  hours,  after 
which  the  insoluble  portion  is  allowed  to  settle,  and  the  solution 
decanted;  this  is  evaporated,  and  leaves  the  yellow  chromate 
of  potash  crystallized.  The  chemical  changes  which  take  place 
in  the  furnace,  are  these:  First,  the  decomposition  of  the  nitre, 
giving  off  oxygen,  which  combines  with  the  oxide  of  chromium, 
and  forms  chromic  acid;  this  unites  with  the  potash  of  the 
nitrate  and  of  the  carbonate,  and  forms  the  yellow  salt,  which 
is  soluble  in  water,  and  afterwards  separated  as  described.  It 
contains  also  soluble  impurities,  such  as  caustic  potash,  silicate 
and  aluminate  of  potash,  which  are  separated  by  the  succeed- 
ing operations  of  boiling  and  crystallization. 

The  bichromate,  which  is  the  salt  used  in  dyeing,  is  pre- 
pared from  the  yellow  salt  obtained  as  above.  Into  a  concen- 
trated solution  is  poured  acetic  or  sulphuric  acid.  The  latter 
acid,  though  often  used,  is  not  well  adapted  for  the  purpose, 
as  the  sulphate  of  potash  formed  is  very  difficult  to  separate 
from  the  chromate,  and  constitutes  a  serious  adulteration. 
Acetic  acid  is  preferable,  and  is  now  generally  employed.  The 
quantity  of  the  acid  is  so  regulated,  that  it  combines  with  the 
one-half  of  the  potash  in  the  yellow  salt,  leaving  two  propor- 
tions of  chromic  acid  in  union  with  the  other  half;  this  process 
may  be  expressed  thus: — 

f  Chromic  acid — ^^-^  Bichromate  of 
2  prop,  yellow  chro-  J  Chromic  acid-^^^^  potash, 
mate  of  potash        Potash  .  .  . 

[  Potash  .  .  .  -  

1  prop!  acetic  acid  .  .  Acetic  acid  .  —  Acetate  of  potash. 

The  solution  of  yellow  chromate  being  concentrated  before  the 
addition  of  the  acetic  acid,  the  bichromate  formed  has  not  so 


CHROME  YELLOW. 


189 


much  water  as  will  hold  it  in  solution,  and  is  therefore  thrown 
down  as  an  orange-colored  powder  ;  this  is  carefully  collected, 
dissolved  in  water,  and  crystallized  by  slow  evaporation. 

When  the  bichromate  of  potash  has  been  prepared  by 
sulphuric  acid,  as  we  stated  above,  it  is  very  liable  to  contain 
sulphate  of  potash,  and  that  often  to  a  great  extent.  This 
salt  may  be  detected  by  dissolving  a  small  quantity  of  the 
chromate  in  distilled  water,  adding  to  it  a  little  pure  nitric 
acid,  and  then  nitrate  of  barytes,  which  will  giye  a  white  pre- 
cipitate if  a  sulphate  be  present.  The  solution  used  in  testing 
should  be  much  diluted.  If  any  chloride  of  potassium  be 
present,  it  may  be  detected  by  adding  a  little  nitrate  of  silver 
to  a  solution  of  the  chromate,  similarly  prepared  by  having  a 
little  nitric  acid  added  to  it;  in  this  case  a  white  precipitate 
results. 

Soda  has  been  tried  in  the  preparation  of  this  salt  to  form 
a  bichromate  of  soda,  which  might  be  equally  useful  to  the 
dyer,  but  this  base  is  not  used  for  the  reasons  already  assigned 
at  page  129. 

Chromate  of  Lead. — The  chromates  of  other  bases  or 
metals  are  obtained  by  adding  solutions  of  their  salts  to  solu- 
tions of  either  the  yellow  or  red  chromate  of  potash.  For 
example,  when  a  salt  of  lead,  e.  g.  the  acetate  or  nitrate,  is 
added  to  a  solution  of  bichromate  of  potash,  the  chromate  of 
lead  is  formed  and  precipitates  as  a  yellow  powder,  constituting 
the  chrome  yellow  dye.  If  this  yellow  precipitate  is  digested 
in  hot  caustic  lye,  a  basic  salt  of  lead  and  chromium  is  formed, 
having  two  proportions  of  lead  and  one  of  chromic  acid  :  it  is 
therefore  a  subchromate  of  lead.  This  is  a  deep  orange  pre- 
cipitate, approaching  to  a  scarlet,  and  constitutes  the  orange 
dye.  If  a  little  chromate  of  lead  (the  grounds  of  the  chrome 
tub)  be  dried,  and  added  to  some  fused  nitre  in  a  crucible  as 
long  as  effervescence  and  red  fumes  are  observed,  and  the 
melted  mass  is  then  poured  out,  there  will  be  at  the  bottom 
some  subchromate  of  lead,  which  may  be  washed  out  by 
wTater;  it  is  of  a*7 rich  vermilion  red,  far  superior  to  anything 
we  have  ever  seen  as  a  dye.  We  would  recommend  it  for 
trial. 

Chrome  Yellow. — The  chromate  of  lead  has  almost  com- 
pletely superseded  the  use  of  vegetable  dyestuffs  in  dyeing 
yellow,  orange,  and  green  upon  cotton  fabrics.  To  dye  a  yellow, 
the  goods  are  immersed  or  wrought  through  a  solution  of  either 
acetate  or  nitrate  of  lead,  from  which,  after  being  tightly 
wrung  or  pressed,  they  are  passed  through  a  solution  of  bi- 
chromate of  potash,  by  which  the  chromate  of  lead  is  formed 
upon  and  within  the  fibre.    The  goods  are  put  several  times 


190 


CHROME  YELLOW. 


through  this  operation  when  deep  shades  are  required;  or, 
what  is  now  more  generally  practised,  the  lead  is  added  to 
lime  as  long  as  the  precipitate  formed  is  redissolved,  and  the 
goods  are  wrought  through  this  solution,  and  then  passed 
through  the  bichromate  solution  ;  or  the  lead  may  be  dissolved 
in  potash  or  soda.  Other  qualities  of  yellow  are  also  obtained 
by  adding  hydrochloric  acid  to  the  solution  of  bichromate  of 
potash,  distinguished  as  acid  yellow.  When  dyeing  yellows 
with  the  acid  gait  of  lead,  and  passing  into  the  chrome  solu- 
tion, there  is  a  great  quantity  of  chromateof  lead  formed  which 
is  not  in  the  fibre :  this  precipitates  to  the  bottom,  and  causes 
considerable  loss.  We  have  already  shown  that  this  chromate 
of  lead  may  be  used  for  making  chromic  acid  ;  it  is  very  solu- 
ble in  alkalies,  and  may  be  made  useful  in  that  way  also  in  the 
dye-house.  When  this  method  of  dyeing  is  practised,  there  is 
a  liability  to  inequality  of  tint.  The  chromate  solution  is  not 
•renewed  each  time,  only  a  little  addition  of  the  chrome  salt 
made  for  each  parcel  of  goods  passing  through  the  dye,  and 
therefore  there  follows  an  accumulation  of  free  acid  in  the 
solution,  which  reacts  upon  the  color,  varying  the  tint  of 
different  lots.  So  well  are  these  circumstances  known  in  prac- 
tice, that  if  yellow  of  a  red  tint  is  required,  or  what  is  termed 
amber,  nitrate  of  lead  is  used  in  preference  to  the  acetate  in 
proportion  to  the  depth  of  redness.  This  gives  free  nitric  acid 
in  the  dye,  which  acts  more  than  the  acetic  acid  upon  the 
bichromate  solution.  The  same  effects  are  produced  by  adding 
a  little  nitric  acid  to  the  chrome  solution.  The  action  of  the 
nitrate  of  lead  added  to  bichromate  of  potash  may  be  thus 
stated.  Suppose  that  100  lbs.  of  cotton  goods  are  to  be  dyed 
yellow,  and  that  they  get  165  ounces  nitrate  of  lead,  which 
is  all  taken  up  by  the  cotton:  this  will  require  74  ounces  of 
bichromate  of  potash.    For,  taking  their  equivalents, 

ATM.   a     f  i    i  (  1    103  Pb  Chromate  of  lead. 

165  Nitrate  of  ead  \  x  ,    Q   ^  Ni      ^  f 

one  equivalent  |£  |N0»31 

14  or  one-half  equi-  ( |  f  50^  Cr03 ' 
valent  of  bichro-  ■<  \  (50|  Cr03 

mate  of  potash    (J    23|KO..  — ^-Nitrate  of  potash 

All  the  lead  used  is  not  imbibed  by  the  cotton,  therefore  much 
less  bichromate  is  required  than  that  given  here,  but  the  action 
is  not  altered  in  relation  to  the  lead  really  fixed  upon  the 
goods.  The  same  reaction  takes  place  when  acetate  of  lead  is 
used,  but  the  free  acetic  acid  does  not  act  so  powerfully  upon 
the  chromate  of  lead  forming  the  dye.  When  subsalts  of  lead 
are  used,  the  action  is  more  regular,  as  no  acid  is  liberated — 


CHROME  ORANGE. 


191 


hence  the  decided  preference  now  given  to  these  salts  in  dye- 
ing.   The  action  is  represented  thus: — 

^  Acetic  acid  Acetate  of  potash. 

Subacetate  of  lead . .  .  •<  Lead  ... 

Lead .... 
(  Potash. 

Bichromate  of  potash  ■<  Chromic  acid  Chromate  of  lead. 

(  Chromic  acid  Chromate  of  lead. 

Were  we  dyeing  100  lbs.  of  cotton  in  different  parcels,  one 
after  the  other,  without  changing  the  liquor,  the  last  parcel 
would  have  the  same  chance  as  the  first  of  being  uniform  in 
the  color,  but  not  so  when  each  parcel  is  accumulating  free 
acid,  which  reddens  the  color.  These  formulae  also  enable  us 
to  appreciate  the  use  of  alkaline  solutions  of  lead — a  practice 
now  often  adopted. 

Chrome  Greens  are  dyed  in  the  same  manner  as  the  yellow, 
the  goods  being  previously  dyed  blue  by  means  of  the  blue 
vat.  For  dyeing  green,  nitrate  of  lead  is  never  used,  the  free 
nitric  acid  would  destroy  the  indigo;  besides,  anything  that 
tends  to  redden  the  hue  is  carefully  avoided,  so  that  the  goods 
are  not  allowed  to  stand  for  any  time  out  of  the  solution  of 
the  bichromate  ;  yet  with  the  greatest  amount  of  care,  there  is 
much  difficulty  in  avoiding  brown  blotches  and  light  parts 
when  acid  salts  of  lead  are  used  ;  but  there  are  fewer  of  these 
difficulties  experienced  when  the  lead  is  either  in  a  subacetate 
state,  or  in  the  state  of  an  alkaline  solution. 

Chrome  Orange  is  obtained  by  fixing  upon  the  goods  the 
subchromate  of  lead,  as  already  described.  This  is  effected  by 
dyeing  the  goods  a  deep  yellow,  and  passing  them  through  a 
strong  hot  alkaline  solution,  which  combines  with  a  portion  of 
the  chromic  acid,  and  leaves  the  subchromate  of  lead  upon  the 
cloth.  We  have  also  already  alluded  to  the  preparation  of  the 
sub  or  basic  salts  of  lead,  and  to  the  proper  proportions,  and 
the  method  of  obtaining  them,  with  their  use  in  dyeing.  The 
alkaline  solution  commonly  used  for  converting  the  chromate 
of  lead  into  the  subchromate  is  lime.  The  reaction  taking 
place  may  be  thus  stated  : — 

[Lead   Subchromate  of  lead. 

2  Chromate  of   J  Lead  .... 
lead  on  cloth  j  Chromic  acid' 
[  Chromic  acid- 

Lime  Lime   Chromate  of  lime. 

The  following  receipt  will  produce  a  good  orange  upon  a 
hundred  pounds'  weight  of  cotton: — 

Thirty  lbs.  of  brown  sugar  of  lead,  and  seventeen  lbs.  of 


192 


CHROME  AS  A  MORDANT. 


litharge  are  put  into  a  boiler  with  about  12  gallons  of  water 
and  boiled  together  for  an  hour  or  so,  until  the  litharge  is 
dissolved  ;  then  a  quantity  of  lime,  from  one  to  two  pounds,  is 
added,  any  sediment  formed  is  allowed  to  settle,  and  the  clear 
fluid  drawn  off'  and  put  into  a  tub  ;  12  lbs.  bichromate  of 
potash  are  dissolved  in  another  tub.  Two  other  tubs,  capable 
of  allowing  10  lbs.  of  yarn  to  be  wrought  in  them  with  free- 
dom, are  rilled,  one  with  water,  to  which  a  little  of  the  lead 
solution  is  added,  and  the  other  with  lime-water;  10  lbs.  of 
the  yarn  (a  bundle)  is  now  wrought  for  some  time  through  the 
tub  containing  the  lead,  wrung  out,  and  put  through  the  lime- 
water  ;  a  little  more  lead  is  added,  another  bundle  is  passed 
through  the  same  tub,  renewing  the  lime-water  each  time.  The 
whole  are  passed  two  or  three  times  through  this  operation, 
according  to  the  depth  of  orange  wanted.  The  bundles  are 
next  wrought  through  a  tub  of  water,  to  which  is  added  some 
of  the  solution  of  the  bichromate  of  potash,  then  passed  through 
the  lead  solution,  and  again  through  the  chrome.  A  satu- 
rated solution  of  newly  slaked  lime  is  brought  to  the  boiling 
point ;  in  this  the  yarn  is  wrought,  either  by  drawing  some  off 
in  tubs,  or  by  the  most  convenient  method  that  circumstances 
will  allow,  until  the  color  is  changed  to  a  deep  orange  or 
scarlet.  It  is  then  taken  out,  passed  through  another  tub 
filled  with  boiling  water,  to  which  is  added  a  small  quantity  of 
solution  of  soap,  soda,  and  oil  ;  afterwards,  it  is  wrung  out 
and  dried  at  a  high  temperature.  The  raising  of  the  orange, 
as  the  hot  liming  is  termed,  is  the  most  trying  operation.  If 
the  lead  has  not  been  properly  prepared,  or  if  there  be  any 
mismanagement  in  the  operation  of  fixing  it  upon  the  fibre, 
the  hot  lime  will  take  all  the  color  off,  leaving  but  a  red  salmon 
shade.  Or  if  the  goods  are  unequally  dyed,  the  color  will 
come  off  in  parts;  and  what  is  still  more  frequently  the  case, 
the  chromate  of  lead  being  entirely  soluble  in  lime-water  at  a 
temperature  a  little  under  boiling,  if  the  lime  solution  is 
allowed  to  become  too  cold,  the  color  will  be  discharged.  The 
lime-water  ought  to  be  at  the  spring  of  the  boil,  and,  as  we  have 
seen  (page  135),  the  higher  the  temperature,  the  less  lime  is 
held  in  solution,  consequently  less  risk  of  failure.  Great  care 
is  necessary,  for  an  orange  being  once  wrong,  it  is  very  diffi- 
cult to  recover. 

Bichromate  of  potash  has  been  very  extensively  used  of  late 
as  a  mordant  for  a  variety  of  .colors  upon  woollen,  and  is 
entirely  superseding  several  of  the  old  processes  for  dyeing 
many  of  the  ordinary  shades,  which  are  very  tedious  in  manipu- 
lation. It  is  also  extensively  used  for  dyeing  catechu  browns 
upon  cotton.    We  may  mention  that  working  much  with  solu- 


VANADIUM. 


193 


tions  of  chrome  and  lead  is  very  injurious  to  the  hands,  espe- 
cially if  there  be  any  part  of  the  skin  broken,  producing  often 
very  severe  sores;  a  solution  of  guttapercha  applied  over  the 
sore,  forming  an  artificial  skin,  has  the  effect  of  preventing 
this  annoyance. 

Tests  for  Bichromate  of  Potash. — Tests  for  the  strength 
and  quality  of  bichromate  of  potash  may  easily  be  formed, 
thus:  Take  pure  nitrate  of  lead,  say  165  grains>  and  dissolve 
in  200  measures  of  water;  this  ought  to  precipitate  74  grains 
of  bichromate;  so  that  it  is  merely  required  to  dissolve  74 
grains  of  bichromate  of  potash,  and  adding  the  nitrate  of  lead 
solution  as  long  as  any  precipitate  takes  place  :  if  all  the  lead 
is  requisite,  the  chrome  is  good,  but  every  three  graduations 
of  the  lead  solution  left,  after  precipitating  all  the  chrome,  will 
represent  about  one  per  cent,  impurity  of  the  bichromate  ;  or 
the  same  method  maybe  taken  as  described  for  lead  (page  174). 
These  operations  are  easy,  and  may  be  performed  by  any  prac- 
tical dyer,  although  little  acquainted  with  chemical  manipula- 
tions. 

The  following  is  the  reaction  of  salts  of  oxide  of  chromium 
with  other  substances  in  solution  : — 


Potash  and  soda    •    .    .    .  . 

Ammonia  

Carbonates  of  the  alkalies  .  . 
Yellow  and  red  prussiates  of 

potash   

Solution  of  galls  ...... 


Greenish  precipitates  solu- 
ble in  excess. 
Grayish  blue  precipitate. 
Light  green  precipitates. 

No  precipitates. 
Greenish  precipitate. 


The  reaction  of  bichromate  upon  reagents  is  as  follows  :  — 

Solutions  of  lead  Yellow  precipitates,  soluble 

in  potash. 

Silver  salts  Bed  brown. 

Zinc  Forms  with  these  salts  a 

double  salt,  which  is 
brown,  and  crystallizes. 

Vanadium  (V  68.6). 

This  metal  was  discovered  in  1830.  It  is  found  in  nature 
combined  with  lead  and  iron,  but  is  exceedingly  rare.  Small 
samples  of  its  oxide,  termed  Vanadic  Acid,  were  sold  at  Is.  6d. 
a  grain.  It  has  a  strong  resemblance  to  chromium  in  many 
of  its  chemical  characters,  and  combines  with  oxygen  in  three 
proportions: — 
13 


194 


TUNGSTENUM. 


Protoxide   =V0. 

Binoxide  .....  =V02. 
Vanadic  acid  =V03. 

There  is  no  combination  of  vanadium  with  an  acid  corre- 
sponding to  the  protoxide,  but  there  are  salts  corresponding 
with  the  binoxide ;  these,  in  solution,  produce  with 

Ammonia       ....  Brown  precipitate. 

Yellow  prussiate  of  potash     .  Yellow  precipitate. 

Eed  prussiate  of  potash  .       .  Green  precipitate. 

Galls      .....  Blue-black  precipitate. 

Sulphurets  of  the  alkalies       .  Brown-black  precipitate. 

Vanadic  acid  combines  with  the  alkalies,  and  forms  a  variety 
of  colored  salts,  nearly  all  soluble  in  water.  All  the  reactions 
of  the  compounds  of  this  metal  give  strong  hopes  that,  were  it 
found  plentifully,  it  would  become  a  useful  substance  in  the 
hand  of  the  dyer;  although  in  the  mean  time,  from  its  price, 
it  is  of  no  importance  to  him. 


TlJNGSTENUM,  OR  WOLFRAM  (W  92). 

This  metal  has  the  appearance  of  iron,  and  exists  in  nature 
chiefly  in  combination  with  lime.  It  was  formerly  the  dearest 
metal  next  to  gold  and  platinum.  It  combines  with  oxygen 
in  two  proportions  : — 

Binoxide  of  Tungsten,  .  .  .  .  =¥02, 
Tungstic  acid   =W03. 

Binoxide  of  tungsten  is  a  brown-red  powder,  which  does  not 
dissolve  in  acids,  and  there  are,  therefore,  no  salts  of  tungste- 
num  corresponding  to  this  oxide.  The  oxide  passes  readily 
into  the  state  of  tungstic  acid  by  combining  with  more  oxygen; 
and  it  is  in  this  state  that  it  is  found  in  nature  forming  a 
tungstate  of  lime.  By  dissolving  this  mineral  in  hydrochloric 
acid,  the  lime  is  dissolved,  and  the  tungstic  acid  remains  as  a 
yellowish  powder,  which  combines  with  alkalies,  and  forms 
soluble  salts.  Acids  added  to  these  salts,  give  yellow  precipi- 
tates, whereas  salts  of  lead,  lime,  and  barium  produce  white 
precipitates. 

If  tungstic  acid  is  dissolved  in  the  sulphuret  of  potassium 
or  of  sodium,  and  an  acid  is  added,  the  tungstenum  is  precipi- 
tated in  the  state  of  sulphuret,  of  a  deep-brown  color,  nearly 
black. 

Tungstate  of  soda  has  been  proposed  for  dyeing.  Textile 
fabrics,  impregnated  with  it,  are  not  inflammable. 


MOLYBDENUM. 


195 


Molybdenum  (Mo  46). 

This  metal  is  obtained  in  nature  combined  with  sulphur. 
The  ore  has  much  the  resemblance  of  plumbago  ;  but  the  metal 
itself  is  white,  resembling  silver,  and  difficult  to  fuse.  It  is 
not  soluble  in  dilute  acids,  but  dissolves  readily  in  aqua  regia. 
It  combines  with  oxygen  in  three  proportions  : — 

Protoxide  ....  =MoO. 

Peroxide  ....    =  Mo02. 

Molybdicacid     ....  =Mo03. 

Th§  protoxide  is  of  a  black  color;  is  difficultly  soluble  in 
acids,  giving  a  black  solution,  not  crystallizable. 

Peroxide  of  Molybdenum  is  obtained  by  digesting  molyb- 
dic  acid  with  hydrochloric  acid  and  copper;  the  solution  has 
a  deep-red  color,  and  by  adding  to  it  an  excess  of  ammonia, 
the  copper  is  dissolved,  and  the  peroxide  of  molybdenum  is 
precipitated.  This  oxide  dissolves  in  acids,  forming  salts  which 
are  red  when  crystallized,  owing  to  the  presence  of  water  ;  but 
when  rendered  anhydrous,  they  become  black. 

Oxalic  acid  dissolves  this  oxide,  and  forms  with  it  a  salt 
which  crystallizes  in  bluish-black  crystals.  These  crystals  are 
soluble  in  water,  and  give  a  red-colored  solution,  from  which, 
if  ammonia  be  added,  a  red-brown  precipitate  is  obtained. 

Molybdic  Acid  is  obtained  by  roasting  the  native  sulphuret 
in  the  air  until  all  the  sulphur  is  evolved;  the  acid  remains 
as  a  powder.  When  required  pore,  this  powder  is  dissolved 
in  ammonia,  and  the  solution  is  evaporated  in  order  to  crystal- 
lize the  acid.  The  crystals  obtained  are  then  submitted  to  a 
moderate  heat  to  drive  off  the  ammonia,  and  the  acid  remains 
pure.  It  is  slightly  soluble  in  water,  but  combines  readily 
with  the  alkalies,  forming  salts,  which  are  all  soluble  in  water, 
and  all  crystallizable.  By  adding  an  acid  to  the  solution  of 
these  salts,  the  molybdic  acid  is  precipitated.  They  act  towards 
reagents  as  follows  : — 

Salts  of  lead  .  .  .  White  precipitate. 
Nitrate  of  silver  .  .  White  precipitate. 
Persalts  of  iron  .       .       .    Yellow  precipitates. 

The  salts  formed  by  dissolving  the  peroxide  in  an  acid,  act 
towards  reagents  as  follows : — 

Solution  of  galls        .       .    Yellowish-red  precipitate. 

Eed  prussiate  of  potash      1  .  , 

■'  i    *     ,    i    >  Brown  precipitates. 
Yellow  prussiate  oi  potash  j  r  r 

Potash  and  soda       .       .    Brownish-black  precipitates. 

Carbonates  of  the  alkalies  .    Light-brown  precipitates. 

Sulphurets  of  the  alkalies  .    Brownish-yellow  precipitates. 


196 


TELLURIUM — ARSENIC. 


Similar  precipitates  may  be  obtained  from  the  salts  of  molybdic 
acid,  by  adding,  along  with  the  reagents,  a  little  hydrochloric 
acid,  to  take  up  the  alkali  of  the  salt. 

Tellurium  (Te  64.2). 

This  is  a  metal  which  is  found  in  combination  with  silver, 
bismuth,  and  lead.  Its  color  is  silver-white,  its  structure 
crystalline  and  brittle;  it  volatilizes  at  a  high  heat,  and  burns 
in  air  with  a  blue  flame.  It  combines  with  oxygen  in  two 
proportions,  both  of  which  have  acid  properties : — 

Tellurous  acid  ....  =Te02. 
Telluric  acid         ....  =Te03. 

Tellurous  Acid  is  a  light,  white,  earthy  powder,  soluble  • 
in  acids,  and  also  in  the  alkalies,  with  which  it  forms  salts 
(tellurites),  which  are  very  soluble  in  water,  and  easily  decom- 
posed. 

Telluric  Acid  may  be  obtained  by  first  fusing  tellurous 
acid  with  nitre,  which  gives  tellurate  of  potash ;  then,  by  dis- 
solving this  salt  and  adding  a  solution  of  barytes,  there  is 
formed  an  insoluble  tellurate  of  barytes,  which  is  again  decom- 
posed by  digestion  in  sulphuric  acid  ;  the  sulphuric  acid  takes 
up  the  barytes,  and  the  telluric  acid  remains  in  solution,  and 
may  be  afterwards  crystallized.  A  tellurate  of  soda  and  potash 
may  be  formed  by  dissolving  these  alkalies  in  the  acid  ;  the}?' 
are  soluble  in  water. 

The  action  of  reagents  upon  the  salts  of  tellurium  is  as 
follows : — 

Alkalies       .       .       .    White  precipitates,  redissolved. 
Yellow  and  red  prussiate  No  precipitate. 
Solution  of  galls    .       .    Yellowish  precipitate. 
Sulphureted  alkalies      .    Brownish  precipitates. 

Arsenic  (As  75). 

This  metal  is  very  abundantly  distributed  in  nature,  and  is 
found  in  various  states  of  combination.  It  is  chiefly,  however, 
associated  with  iron,  nickel,  and  cobalt.  Arsenic  has  a  gray- 
steel  lustre,  is  brittle,  crystalline,  and  very  easily  sublimed, 
rising  in  vapor  at  a  heat  of  about  356°,  and  is  thus  easily  sepa- 
rated from  its  ores.  It  combines  with  oxygen  in  three  dif- 
ferent proportions:  First,  a  grayish  oxide,  probably  suboxide, 


ARSENIOUS  ACID. 


197 


which  forms  upon  the  surface  of  the  metal  by  exposure  to  air; 
and 

Arsenious  acid  ....  =As03. 
Arsenic  acid      .       .       .       .  =As05. 

Arsenious  Acid. — This  is  plentiful  in  commerce  as  white 
oxide  of  arsenic;  it  is  a  heavy  white  opaque  mass  as  sublimed, 
although  generally  sold  in  the  market  as  a  powder  and  in 
crystals.  This  acid  is  dissolved  by  boiling  water,  in  the  pro- 
portion of  about  1  part  to  10  of  water;  but  on  cooling,  the 
solution  deposits  nearly  three-fourths  of  this  quantity.  It  has 
little,  if  any,  taste,  but  is  notoriously  a  deadly  poison.* 

It  dissolves  in  hydrochloric  acid  in  much  greater  quantity 
than  in  water,  but  does  not  combine  with  the  acid  (see  Chlo- 
rine). It  is  rapidly  dissolved  in  hot  solutions  of  bitartrate  of 
potash,  and  forms  a  crystallizable  salt. 

It  is  dissolved  also  in  great  quantity  by  solutions  of  potash 
and  soda,  and  also,  but  not  so  effectually,  by  the  carbonates  of 
these  alkalies. 

This  acid,  as  before  mentioned  (page  169),  is  used  in  the 
dye-house  for  dyeing  Scheele's  green  {arsenic  sages)]  but  we 
are  convinced  that  similar  colors  might  be  produced  by  other 
means ;  and  there  cannot  be  a  doubt  but  that  any  process  which 
would  supersede  its  use  would  benefit  all  who  are  engaged  in 
the  preparation  of  such  goods.  Common  humanity,  indeed, 
dictates  its  complete  abandonment  as  a  dye.  Nor  is  the  evil  so 
much  in  the  operations  of  dyeing,  as  in  those  that  succeed: 
persons  who  have  occasion  to  work  with  the  yarns  after  they 
are  dyed,  suffer  more  severely  than  the  dyers.  The  color  being 
merely  a  precipitate  of  the  arsenite  of  copper  (a  most  deadly 
poison)  upon  the  fibre  of  the  yarn,  to  which  it  but  loosely 
adheres,  it  is  readily  disengaged  as  dust  in  the  dry  state,  and  in 
the  process  of  winding,  especially,  much  of  it  is  unavoidably 
inhaled  by  the  unfortunate  operative.  The  result  is,  as  might 
be  expected,  that  health  is  seriously  impaired,  and  not  unfre- 
quently  the  consequences  are  fatal.  It  is,  in  fact,  consistent 
with  our  knowledge,  that  individuals  of  this  class  have  never 

*The  best  antidote  for  arsenic,  when  taken  into  the  stomach,  is  newly 
precipitated  peroxide  of  iron.  This  can  always  be  obtained  in  a  very  few 
minutes  in  the  dye-house,  by  adding  to  the  nitrate,  or  any  other  /?er-solutions 
of  iron,  a  little  potash  or  soda  ;  the  iron  is  immediately  precipitated.  The 
precipitate  ought  first  to  be  washed  with  water,  and  then  taken  in  the  gelati- 
nous state.  The  arsenious  acid  in  the  stomach  receives  oxygen  from  the 
peroxide  of  iron,  and  is  converted  into  arsenic  acid,  which  combines  with  the 
protoxide  of  iron,  which  is  not  poisonous.  Should  arsenic  be  taken  into  the 
stomach  in  the  state  of  arsenic  acid,  protoxide  of  iron  will  serve  the  same 
purpose  as  the  peroxide,  and  is  obtained  by  precipitating  some  copperas,  by 
means  of  an  alkali. 


198 


SULPHURETS  OF  ARSENIC. 


recovered  from  the  effects  of  winding  a  quantity  of  arsenic  sage 
yarn,  for  which  they  were  paid  one  shilling  !  Warpers  also  are 
subjected  to  the  same  baneful  evil,  although  in  a  less  degree, 
and  even  the  weaver  is  not  exempt  from  it.  Altogether,  indeed, 
the  injury  to  the  community  by  the  use  of  this  dye  outweighs 
a  hundredfold  that  arising  from  the  unrestricted  sale  of  poisons, 
against  which  so  loud  a  protest  was  lately  raised.  We  are  con- 
vinced, moreover,  that  it  is  a  gratuitous  evil,  and  that  dyers 
would  very  soon,  under  the  pressure  of  a  little  public  opinion, 
find  means  of  avoiding  it,  and  producing  the  color  innocuously, 
and  of  an  innocuous  character. 

Arsenic  Acid. — This  acid  is  made  by  heating  arsenious  acid 
with  about  its  own  weight  of  water,  and  when  at  the  boiling 
point  adding  nitric  acid,  as  long  as  red  fumes  are  given  off:  the 
whole  is  then  evaporated  to  dryness,  to  expel  any  excess  of 
nitric  acid  that  may  be  present.  The  heat  of  the  mass,  when 
dry,  must  not  be  high,  otherwise  the  arsenic  acid  will  be  de- 
composed. Arsenic  acid  is  milk-white,  deliquesces,  and  is  solu- 
ble in  water:  its  solution  having  a  sour  taste,  and  strong  acid 
reactions. 

When  an  equivalent  of  arsenic  acid  is  ignited  with  an  excess 
of  carbonate  of  soda  or  potash,  a  subsalt  is  formed,  which  is 
soluble  in  water,  and  easily  crystallized.  Salts  of  the  alkalies 
are  also  formed  by  adding  arsenic  acid  to  hot  solutions.  These 
salts  crystallize,  and  their  solutions  in  water  give  white  precipi- 
tates with  the  solutions  of  the  earths  and  their  salts.  Solu- 
tions of  the  salts  of  lead  also  give  white  precipitates  ;  nitrate  of 
silver  a  precipitate  of  a  brown  color  ;  and  salts  of  copper  pro- 
duce green  precipitates.  These  salts  can  all  be  made  available 
in  the  dye-house,  although,  for  the  reasons  above  stated,  it 
would  be  well  if  substitutes  were  used. 

Sulphurets  of  Arsenic. — There  are  two  compouuds  of  sul- 
phur and  arsenic,  which  are,  or  rather  were,  occasionally  used 
in  the  dye  house.    These  are — 


The  first  of  these  can  be  prepared  by  fusing  arsenic,  or  arse- 
nious acid,  with  sulphur;  it  is  transparent,  and  of  a  fine  ruby 
color. 

The  latter  may  be  prepared  by  adding  to  a  solution  of  arse- 
nious acid  in  hydrochloric  acid,  a  sulphuret  of  an  alkali,  either 
potash  or  soda;  it  is  precipitated  of  a  rich  yellow  color,  and  is 
much  used  in  painting,  under  the  name  of  king's  yellow. 

Both  of  these  sulphurets  are  found  native.  Their  principal 
use  in  the  dye-house  was  in  the  blue  vat. 


Realgar 
Orpiment 


=  As  S2. 
=  As  S3. 


ANTIMONY. 


199 


Arsenic  combines  readily  with  hydrogen,  and  forms  a  gas, 
arseniureted  hydrogen,  which  is  very  poisonous.  When  arsenic 
is  present  in  any  solution  from  which  hydrogen  is  being  given 
off,  arseniureted  hydrogen  is  formed,  and  therefore  care  ought 
to  be  taken  not  to  breathe  any  of  the  gas.  Sulphuric  acid  (see 
page  98)  often  contains  arsenic. 


Antimony  (Sb  129). 

This  metal  is  found  in  considerable  abundance  associated 
with  sulphur,  which  is  separated  from  it  by  roasting.  Anti- 
mony is  a  bright  and  white  metal,  of  a  crystalline  structure, 
very  brittle,  and  not  oxidized  by  exposure  to  the  air.  It  vol- 
atilizes at  a  high  heat,  and  oxidizes  or  burns  at  a  red  heat, 
when  exposed  to  the  air ;  it  then  passes  off  in  white  fumes. 
Antimony  combines  with  oxygen  in  two  principal  proportions, 
forming — 

Oxide  of  antimony  =Sb2  03. 

Antimonic  acid     ......    =Sb2  05. 

Oxide  of  Antimony  may  be  prepared  either  by  sublimation, 
as  already  stated,  or  by  precipitation  from  a  solution  of  any 
of  its  salts,  by  an  alkali. 

When  the  sulphuret  of  antimony  (the  common  ore)  is  di- 
gested in  strong  hydrochloric  acid,  the  metal  dissolves,  and 
forms  a  chloride  of  antiinony;  or  rather,  a  sesquichloride,  as 
follows: — 

Sulphuret  of  antimony  {  &  Z^^tt^' 


Three  proportions  of 

hydrochloric  acid        \3C1.  :::::^Chioride  of  antimony. 

The  clear  solution  being  poured  off,  and  heated  to  the  boil- 
ing point,  carbonate  of  potash  or  soda  is  then  added,  and  the 
antimony  is  precipitated  in  the  state  of  oxide  as  a  white  pow- 
der.   Both  potash  and  soda  dissolve  this  oxide. 

Sulphate  of  Antimony  may  be  prepared  by  digesting  the 
sulphuret  in  strong  sulphuric  acid  with  the  aid  of  heat;  or  the 
metal  may  be  substituted  for  the  sulphuret. 

All  the  acid  salts  of  antimony  are  decomposed  by  aqueous 
dilution:  an  insoluble  oxychloride  is  thereby  formed  and  pre- 
cipitated as  a  white  powder.  There  are,  however,  several  dou- 
ble salts  of  antimony  with  other  substances,  which  are  soluble, 
and  not  precipitated  by  dilution.  Thus,  when  a  strong  solution 
of  binoxalate  of  potash  is  heated,  and  oxide  of  antimony  added, 
a  salt  is  formed,  which  is  soluble  in  water,  and  from  which  the 


i 


200 


URANIUM. 


antimony  is  not  precipitated  by  dilution.  Again,  when  oxide 
of  antimony  is  boiled  in  water,  and  tartrate  of  potash  added, 
a  double  salt  (tartar  emetic)  is  formed,  which  crystallizes,  and 
is  not  precipitated  by  dilution. 

Some  chemists  recognize  an  Antimonious  Acid,  which  is 
obtained  by  oxidating  or  acting  upon,  metallic  antimony  with 
nitric  acid.  It  is  also  formed  when  sulphate  of  antimony  is 
roasted.  Some  doubts  exist  as  to  the  true  nature  of  this  com- 
pound; it  is  probably  a  mixture  of  oxide  of  antimony  with  an- 
timonic  acid  (thus  Sb203+Sb205),  having  the  same  elements  as 
two  proportions  of  antimonious  acid  =2Sb204.  The  combina- 
tions of  this  acid  have  not  been  studied. 

Antimonic  Acid  is  prepared  in  the  same  manner  as  described 
for  arsenic  acid,  that  is,  by  acting  upon  the  oxide  with  nitric 
acid,  and  expelling  any  excess  of  the  acid  by  heat.  Antimonic 
acid  is  a  pale-yellow  powder,  not  soluble  in  water,  but  soluble 
in  potash  and  soda,  with  which  it  forms  antimoniates,  which, 
however,  are  not  stable,  and  are  decomposed  by  almost  any 
other  acid  or  salt. 

The  precipitates  formed  by  reagents  with  salts  of  antimony 
are  nearly  all  white,  but  when  a  sulphuret  of  any  of  the  alka- 
lies is  added  to  a  solution  of  antimony,  a  beautiful  golden  yel- 
low precipitate  is  formed. 


Uranium  (U  60). 

This  rare  metal  is  a  component  of  the  mineral  named  pitch- 
blende, which  contains  several  other  metals.  Its  metallic  cha- 
racteristics have  only  been  recently  ascertained;  indeed,  one  of 
its  oxides  was,  till  lately,  regarded  as  an  element.  It  is  a  white- 
colored  metal  very  like  silver,  but  is  peculiar  in  being  very  in- 
flammable, burning  with  great  brightness  at  a  low  red  heat. 
It  combines  with  oxygen  in  several  proportions,  but  only  two 
of  its  oxides  are  soluble  in  acids,  and  form  corresponding  salts, 
These  are  the 

Protoxide  =U0. 

Peroxide  =  U203. 

Protoxide  of  Uranium  is  obtained  by  acting  upon  the  min- 
eral above  named,  by  aqua  regia,  and  separating  it  from  the 
various  other  metals  with  which  it  is  associated,  by  precipita- 
tion. When  a  solution  of  uranium  in  an  acid  is  precipitated 
by  an  alkali,  and  the  alkali  is  well  washed  out,  the  remainder 
is  in  the  state  of  protoxide.  This  oxide  dissolves  with  diffi- 
culty in  hydrochloric  acid,  but  more  freely  in  dilute  sulphuric 


CEKIUM. 


201 


acid  with  the  aid  of  heat,  and  gives  a  green  solution,  which 
yields  similarly  colored  crystals.  It  is  very  soluble  in  nitric 
acid,  forming  a  nitrate.  These  salts  give  the  following  reac- 
tions:— 


Carbonates  of  the  alkalies  .  .  Greenish  precipitates. 
Yellow  prussiate  of  potash  .  .  Eeddish-brown  precipitate. 
Eed  prussiate  of  potash  .  .  .  Eeddish-brown  precipitate, 

after  a  time. 

Sulphurets  of  the  alkalies  .  .  Black  precipitates. 

Peroxide  of  Uranium  is  obtained  by  precipitation  from  a 
solution  of  the  mineral  by  means  of  an  alkali;  the  precipitate 
is  collected,  but  the  alkali  is  not  washed  out,  and  the  residue  is 
then  exposed  to  a  red  heat;  the  presence  of  the  alkali  prevents 
the  metal,  which  is  present  as  a  peroxide,  from  passing  into 
the  protoxide  state.  When  thus  treated  the  oxide  is  stable. 
Ammonia,  however,  will  not  serve  as  the  precipitant  in  this 
case,  as,  on  account  of  its  volatile  nature,  it  would  be  dissipated 
by  the  heat  to  which  the  precipitate  must  be  exposed. 

The  peroxide  of  uranium  has  a  beautiful  yellow  color,  and 
is  soluble  in  all  the  acids,  and  forms  persalts.  The  solutions 
of  these  salts  act  towards  reagents  as  follows: — 

Alkalies  and  their  carbonates  .  .  Yellow  precipitates. 
Yellow  prussiate  of  potash  ....  Eeddish-brown  precipitate. 

Eed  prussiate  of  potash  No  precipitate. 

Solution  of  galls  Dark  brown  precipitate. 

Sulphurets  of  the  alkalies  ....  Brown  precipitates. 

It  may  be  inferred  from  these  reactions  that,  could  this  metal 
be  obtained  in  sufficient  quantity,  it  would  form  a  valuable  ad- 
dition to  the  dyer's  coloring  matters.  At  present,  however,  it 
is  too  scarce  to  be  regarded  as  of  any  practical  importance. 


This  metal  is  obtained  in  small  quantities  from  several  mine- 
rals, found  chiefly  in  Sweden  and  Greenland.  These  are  acted 
upon  by  aqua  regia,  and  the  metal  is  separated  by  reagents. 
Hitherto,  it  has  been  obtained  only  as  a  powder  of  a  brownish- 
black  color,  which  is  rapidly  decomposed  in  water.  With  oxy- 
gen it  forms 


Alkalies 


Brownish  precipitates. 


Cerium  (Ce  47). 


Protoxide 
Peroxide 


=  Ce  O. 

=  Ce203. 


202 


MERCURY. 


The  oxides  and  salts  of  cerium  are  mostly  white,  but  have  not 
been  subjected  to  any  close  investigation.  Eeagents  generally 
give  white  precipitates  with  solutions  of  the  salts. 

Mercury  (Hg  100). 

This  metal  is  found  abundantly  both  in  the  metallic  state  and 
in  combination  with  sulphur,  forming  the  mineral  cinnabar, 
from  which  the  metal  is  distilled,  by  heating  it  with  iron  and 
lime.  Mercury  at  ordinary  temperatures  is  liquid;  hence  its 
popular  name  of  quicksilver  ;  it  has  a  high  metallic  lustre,  be- 
comes solid  at  40°  below  zero,  and  gaseous  at  662°.  It  com- 
bines with  oxygen  in  two  well-known  proportions: — 

Suboxide  =  Hg20. 

Protoxide  =  Hg  O. 

Suboxide  of  Mercury  is  a  black  powder,  and  is  obtained 
by  precipitation  from  a  cold  solution  of  subnitrate  of  mercury 
by  potash  or  soda.  It  dissolves  in  acids,  and  forms  a  series  of 
salts  of  great  use  in  medicine.  The  common  calomel  of  the 
druggists  is  a  subchloride  of  mercury  =  Hg2  CI.  The  subsalts 
of  mercury  give  the  following  reactions: — 


Alkalies  

Carbonates  of  the  alkalies  .  . 

Yellow  prussiate  of  potash  . 
Eed  prussiate  of  potash     .  . 

Solution  of  galls  

Bichromate  of  potash  .  .  . 
Sulphurets  of  the  alkalies  .  . 


Black  precipitates. 

White  precipitates,  which  be- 
come black  by  heating. 
White  precipitate. 
Reddish-brown  precipitate. 
Light  yellow  precipitate. 
Red  precipitate. 
Black  precipitates. 


Protoxide  of  Mercury,  Peroxide  of  Mercury. — This 
oxide  is  obtained  by  heating  mercury  in  contact  with  oxygen, 
or  by  exposing  nitrate  of  mercury  to  heat  until  all  the  acid  is 
expelled.  Its  color  is  a  deep  red,  and  hence  it  is  known  in 
commerce  as  red  precipitate. 

When  mercury  is  acted  upon  by  an  acid,  persalts  are  gene- 
rally formed.  These  salts  may  also  be  formed  by  dissolving 
the  red  oxide  in  the  acids.  Thus  the  perchloride  (corrosive  sub- 
limate) may  be  prepared  by  dissolving  the  red  oxide  in  hydro- 
chloric acid.  There  are  a  great  variety  of  salts  of  mercury, 
nearly  all  poisonous,  and  all  less  or  more  used  in  medicine. 
None  of  them  are  used  in  dyeing,  but  some  are  useful  as  tests. 
The  following  are  their  reactions  with  other  substances: — 


SILVER. 


203 


Potash  and  soda   Yellow  precipitates. 

Ammonia   White  precipitate. 

Carbonates  of  the  alkalies.  .  Reddish-brown  precipitate. 

Carbonate  of  ammonia .  .  .  .  White  precipitate. 

Yellow  prussiate  of  potash  .  White  precipitate. 

Eed  prussiate  of  potash  .  .  .  Yellow  precipitate. 

Solution  of  galls   No  precipitate. 

Iodide  of  potassium   Red  precipitate. 

Bichromate  of  potash  ....  Red  precipitate. 
Sulphurets  of  the  alkalies  .  .  Black  precipitates. 

These  colors  are  not  generally  permanent  upon  cotton,  but 
are  destroyed  when  exposed  to  a  moderate  heat. 


Silver  (Ag  108). 

This  metal  is  found  in  considerable  abundance  in  nature,  and 
is  very  widely  diffused;  it  is  generally  in  combination  with 
sulphur,  along  with  other  metals,  particularly  with  lead.  It  is 
obtained  from  the  lead  ores  of  this  country,  and  is  extracted 
from  them  by  cupellation,  as  was  described  under  the  head  of 
Litharge  (page  170).  It  is  also  extracted  from  its  sulphurets, 
and  from  some  other  ores  which  are  found  abroad,  from  which 
the  greater  quantity  of  the  silver  is  obtained,  by  roasting  the 
ore,  after  mixing  with  it  a  quantity  of  common  salt,  which 
converts  the  silver  into  a  chloride.  The  ore  is  next  put  into 
large  barrels  with  water  and  scraps  of  metallic  iron  and  mer- 
cury, and  the  barrels  are  kept  revolving,  in  order  thoroughly 
to  mix  their  contents.  The  iron  decomposes  the  chloride  of 
silver,  and  becomes  a  chloride  of  iron,  and  the  mercury  takes 
the  liberated  silver,  and  forms  with  it  an  amalgam.  The  reac- 
tions may  be  thus  represented:  — 


Chloride  of  silver 


f  Ag  ;  Amalgam  of  silver. 

(01. 

Mercury .    .  . 

Iron  Fe.  Chloride  of  iron,  soluble. 


The  amalgam  is  collected  and  subjected  to  a  high  heat  in  a  re- 
tort; the  mercury  is  thereby  distilled  over,  and  the  silver  re- 
mains behind. 

Silver  is  the  whitest  of  all  the  metals;  it  is  also  highly  duc- 
tile and  malleable,  and  does  not  combine  with  oxygen  by  ex- 
posure to  the  air,  but  is  very  soon  tarnished  by  the  fumes  of 
sulphur,  which  always  exist  to  some  extent  in  localities  where 
coal  is  burned.  Silver  combines  with  oxygen  in  three  propor- 
tions:— 


204 


SILVER. 


Suboxide 
Protoxide 
Peroxide 


=  Ag20. 
=  Ag  O. 


The  first  and  last  of  these  oxides  are  little  known;  the  prot- 
oxide is  of  the  most  importance,  and  is  obtained  as  a  deep 
brown  powder,  by  adding  an  alkali  to  the  solution  of  any 
soluble  salt  of  silver.  This  oxide  dissolves  in  acids,  and  forms 
protosalts. 

Nitrate  of  Silver. — Nitric  acid,  diluted,  dissolves  silver  by 
the  aid  of  heat  with  great  ease;  and  the  nitrate  formed  is  the 
salt  commonly  used  in  the  laboratories.  It  is  very  corrosive, 
blackens  the  skin,  and  constitutes  the  permanent  marking-ink 
for  linen,  which,  by  the  way,  may  be  easily  obliterated  by  dip- 
ping the  cloth  in  chlorine  water.  The  chlorine  converts  the 
silver  into  a  chloride,  which  is  washed  out  by  passing  the  cloth 
through  liquid  ammonia. 

Sulphate  of  Silver. — Silver  is  dissolved  by  hot  sulphuric 
acid,  and  forms  a  sulphate  of  silver.  This  salt  crystallizes,  and 
is  very  corrosive,  but  it  is  little  used. 

The  attraction  of  silver  for  chlorine  is  so  great  that  hydro- 
chloric acid,  or  any  chloride,  added  to  a  salt  of  silver,  instantly 
decomposes  it,  and  converts  the  silver  into  an  insoluble  chlo- 
ride. Hence  it  is  that  chlorides  are  the  best  tests  for  silver, 
and  that  silver  is  in  turn  the  best  test  for  chlorine. 

Oxide  of  silver  is  soluble  in  acetic  acid,  and  many  of  the 
milder  acids;  and  several  of  its  salts  are  now  extensively  used 
for  photographic  purposes. 

Chloride  of  silver  is  soluble  in  hyposulphite  of  soda,  forming 
a  salt,  which  is  also  much  used  in  obtaining  pictures  by  means 
of  light;  the  study  of  the  action  of  light  upon  these  salts  is 
indeed  well  worthy  the  attention  of  dyers  (page  29),  as  the 
phenomena  are  highly  suggestive  of  practical  application. 

When  experimenting  with  salts  of  silver,  it  is,  of  course,  im- 
portant that  none  of  the  metal  be  lost;  and  it  may  be  all  re- 
covered by  converting  it  into  chloride,  or  evaporating  the  solu- 
tion in  the  case  of  hyposulphites,  and  when  dry,  mixing  with 
three  times  its  weight  of  dry  carbonate  of  potash,  putting  this 
into  a  crucible,  and  fusing  for  fifteen  minutes:  when  the  cruci- 
ble cools,  the  metallic  silver  will  be  found  as  a  button  of  metal 
at  the  bottom. 

The  salts  of  silver  have  the  following  reactions  with  other 
substances: — 


GOLD. 


205 


Potash  and  soda 
Ammonia    .  . 


Carbonates  of  the  alkalies  , 
Yellow  prussiate  of  potash 
Eed  prussiate  of  potash  . 
Solution  of  galls   .    .  . 
Bichromate  of  potash 
Sulphurets  of  the  alkalies 


Brown  precipitates. 

Brown  precipitate,  very  soluble 

in  excess. 
White  precipitates. 

White  precipitate. 

Red-brown  precipitate. 

No  precipitate. 

Crimson-red  precipitate. 

Black  precipitates. 


The  necessary  expense  of  this  metal  prevents  its  introduction 
to  the  dye-house;  and  we  are  afraid  that  its  property  of  be- 
coming black  by  light  would  destroy  its  general  usefulness, 
even  could  it  be  had  sufficiently  cheap. 


Gold  (Au  197  or  98.5). 

This  metal  is  commonly  found  in  the  metallic  state,  and  nearly 
pure,  but  sometimes  it  is  associated  with  other  metals;  it  is  ex- 
tensively diffused  through  nature.  When  it  is  found  along 
with  silver,  the  ore  is  treated  in  the  same  way  as  the  other  ores 
of  silver,  and  the  two  metals  are  obtained  together  in  alloy ; 
but  when  the  metal  is  diffused  through  the  rock,  in  the  metal- 
lic state,  the  rock  is  stamped  to  fine  powder,  and  then  submit- 
ted to  a  current  of  water,  which  carries  away  the  light  earthy 
portion,  and  the  gold  falls  to  the  bottom  from  its  superior 
weight.  This  residuum  is  mixed  with  metallic  mercury,  to  form 
an  amalgam  with  the  gold,  which  is  afterwards  distilled  in  the 
same  manner  as  was  described  for  silver. 

Gold  and  silver  are  separated  by  subjecting  the  alloy  to  nitric 
or  strong  sulphuric  acid,  which  dissolves  the  silver  and  leaves 
the  gold.  The  silver  is  precipitated  as  a  chloride,  and  reduced, 
by  fusion  with  carbonate  of  potash,  an  operation  which  is  termed 
parting. 

Gold  is  the  only  yellow  metal  known;  it  is  the  most  ductile 
as  well  as  the  most  malleable  of  the  metals,  and  does  not  oxi- 
date or  tarnish  by  exposure  to  the  air,  which  gives  it  an  intrin- 
sic value  over  most  of  the  other  metals.  It  does  not  dissolve 
in  any  single  acid,  but  is  readily  acted  upon  by  aqua  regia, 
forming  a  perchloride.  It  combines  with  oxygen  in  two  pro- 
portions:— 

Suboxide  =Au2  O. 

Peroxide  =  Au2. 03. 

The  first  of  these  oxides  is  obtained  by  adding  a  solution  of 
potash  to  subchloride  of  gold:  it  is  a  green  powder. 


206 


PLATINUM. 


The  peroxide  is  obtained  by  precipitating  the  solution  of  gold 
in  aqua  regia  by  magnesia,  and  washing  the  precipitate  by  a 
little  nitric  acid.    This  oxide  is  of  a  brown  color. 

Subchloride  of  Gold  is  prepared  by  evaporating  a  solution 
of  gold  in  aqua  regia  to  dryness,  and  heating  the  residue  to 
about  400°,  until  all  smell  of»chlorine  has  ceased,  stirring  all 
the  while.  The  product  is  the  subchloride,  and  is  decomposed 
by  water. 

Perchloride  of  Gold. — This  is  the  salt  obtained  by  dis- 
solving the  metal  in  aqua  regia;  but  which  may  be  had  purer 
by  dissolving  the  peroxide  in  hydrochloric  acid.    Thus: — 


Peroxide  of  gold  .  .  {  £u;  -  Perchloride  of  gold 


( 3C 

3  Hydrochloric  acid  ^  g  Water_ 

This  salt  is  yellow,  but  when  it  touches  the  skin  it  dyes  it  of 
a  deep  purple.    Its  reactions  are  as  follows : — 

Potash  and  soda     .       .       .       No  precipitate. 
Ammonia      ....       Yellow  precipitate. 
Oxalic  acid    ....       Dark-greeri  precipitate. 
Yellow  prussiate  of  potash     .       Light-green  precipitate. 
Eed  prussiate  of  potash         .       No  precipitate. 
Protosalts  of  iron  .       .       .       Brown  (metallic  gold)  pre- 
cipitates. 

Protosalts  of  tin  .       .       Purple  precipitates. 

Solution  of  galls     .       .       .       Black  precipitate,  which  be« 

comes  brown  (metallic  gold) 

Salts  of  this  metal,  on  account  of  their  expense,  can  only 
be  used  as  reagents  in  the  laboratory,  not  in  manufacturing 
operations. 


Platinum  (Pt  98.7). 

This  metal  is  found  in  a  native  state  in  the  debris  of  rocks 
belonging  to  the  earliest  igneous  formation.  It  was  first  dis- 
covered in  the  auriferous  sands  of  some  rivers  in  America,  but 
is  now  found  in  various  localities;  and  comes  principally  from 
Siberia.  Platinum  is  a  white  metal,  very  ductile,  and  also  malle- 
able ;  it  is  the  densest  metal  known,  and  is  not  acted  upon  by 
exposure  to  the  air,  nor  oxidized  by  heat.  No  single  acid 
affects  it,  on  which  account  it  is  exceedingly  useful  in  many 
chemical  processes.  Aqua  regia  dissolves  it  with  the  aid  of 
heat,  and  forms  with  it  a  perchloride.  It  combines  with  oxygen 
in  two  proportions: — 


PALLADIUM. 


207 


Protoxide  =Pt  0. 

Peroxide  =Pt  02. 

The  protoxide  is  obtained  by  digesting  the  protochloride  in 
potash  ;  it  is  a  black  powder,  soluble  in  excess  of  potash,  yield- 
ing a  green  solution,  from  which  the  platinum  may  be  precipi- 
tated. 

The  protochloride  is  obtained  in  the  same  manner  as  the 
protochloride  of  gold  ;  it  is  a  greenish  powder,  slightly  soluble 
in  strong  hydrochloric  acid. 

The  peroxide  of  platinum  is  obtained  by  adding  to  a  solution 
of  sulphate  of  platinum  some  nitrate  of  barytes;  the  sulphuric 
acid  is  precipitated,  and  nitrate  of  platinum  is  formed,  which 
remains  in  solution.  By  adding  to  this  solution  a  little  soda, 
peroxide  of  platinum  is  precipitated  as  a  reddish-brown  powder. 
This  oxide  dissolves  in  acids,  forming  salts,  which  are  mostly 
of  a  brownish-red  color,  and  has  a  strong  attraction  for  the 
earthy  bases. 

The  sulphate  is  prepared  by  adding  to  a  solution  of  plati- 
num in  aqua  regia,  drop  by  drop,  a  solution  of  sulphuret  of 
potassium,  which  forms  a  bisulphuret  of  platinum;  by  expo- 
sure to  the  air,  the  sulphur  extracts  oxygen,  and  becomes 
sulphuric  acid,  which  combines  with  the  metal. 

Bichloride  of  platinum  is  the  salt  formed  when  the  metal  is 
dissolved  in  aqua  regia;  it  has  a  deep-red  color.  This  salt 
combines  with  chloride  of  potassium,  and  forms  with  it  a 
double  salt,  which  crystallizes  in  beautiful  reddish-yellow  crys- 
tals. The  persalts  of  platinum  are  all  more  or  less  red  in  color, 
and  have  the  following  reactions  with  other  substances: — 

Potash,  soda,  ammonia,  and  )  y  n  .  . 

their  carbonates    .    .    .     j  r  r 

Yellow  prussiate  of  potash  Yellow  precipitate. 
Bed  prussiate  of  potash  .  Yellow  precipitate. 
Solution  of  galls  ....       No  precipitate. 

"  A  reddish  brown  colored  solu- 
tion, the  tin  being  rendered 
Protochloride  of  tin  .    .    .    -{      a  perchloride,  the  platinum 

a  protochloride ;  but  there  is 
no  precipitate. 

Sulphurets  of  the  alkalies        Beddish-brown  precipitates. 


Palladium  (Pd  53.3). 


This  metal  is  found  associated  with  platinum  ;  its  appearance 
is  very  similar,  except  that  it  has  a  slightly  reddish  tint,  and 


208 


IRIDIUM. 


only  about  half  the  density.  It  is  nearly  as  infusible,  but  its 
surface  slightly  tarnishes  by  exposure  to  air,  and  it  is  soluble 
in  nitric  acid.  Like  platinum,  it  combines  with  oxygen  in  two 
proportions : — 

Protoxide  =Pd  0. 

Peroxide  =Pd  02. 

The  protoxide  is  a  dark-brown  powder,  and  is  obtained  by 
dissolving  the  metal  in  nitric  acid,  evaporating  to  dryness,  and 
heating  the  residue  to  drive  off  the  acid ;  or  it  is  precipitated 
from  the  acid  by  an  alkaline  solution. 

The  protochloride  of  palladium  is  formed  by  dissolving  the 
metal  in  hydrochloric  acid,  to  which  a  few  drops  of  nitric  acid 
have  been  added.  The  former  acid  acts  upon  the  metal  slowly 
when  alone,  but  this  addition  quickens  the  action.  The  solution 
is  evaporated  to  dryness,  to  expel  any  excess  of  acid,  and 
yields  a  compound  of  a  dark-brown  color,  which  is  protochlo- 
ride. This  salt  combines  with  chloride  of  potassium  and 
sodium,  and  forms  double  salts,  which  deposit  yellow-colored 
crystals  from  their  solutions. 

The  peroxide  of  palladium  is  obtained  by  first  dissolving  the 
metal  in  strong  aqua  regia ;  this  gives  a  solution  of  a  dark- 
brown  color,  which  is  a  bichloride  of  the  metal.  To  this  solution 
is  added,  gradually,  either  potash  or  soda,  which  precipitates 
the  metal  as  a  hydrated  peroxide  of  a  reddish-brown  color. 
The  salts  corresponding  to  the  peroxide  are  little  known. 
Solutions  of  the  protosalts  of  palladium  act  towards  reagents 
as  under: — 

Brownish  precipitates. 
No  precipitate. 
Brown  precipitates. 

No  precipitates. 

Black  precipitate. 
Brown  precipitate. 
Black  precipitates. 

Iridium  (Ir  99). 

This  metal  is  found  combined  with  platinum,  which,  like 
palladium,  it  also  resembles  in  appearance.  It  is  more  infusi- 
ble than  platinum,  and,  if  pure,  resists  the  action  of  all  the 
acids;  but  when  alloyed  with  platinum,  it  is  soluble  in  aqua 
regia.  It  is  known  to  combine  with  oxygen  in  four  propor- 
tions, forming — 


Potash  and  soda 
Ammonia  . 

Carbonates  of  potash  and  soda  . 
Yellow  and  red  prussiates  of ) 
potash  j 
Protochloride  of  tin  . 
Phosphate  of  soda 
Sulphurets  of  the  alkalies  . 


OSMIUM— RHODIUM. 


209 


Protoxide   =IrO. 

Sesquioxide     .....  =lr203. 

Binoxide   =Ir  02. 

Peroxide   =  Ir  03. 

To  all  of  which  there  are  corresponding  chlorides  known.  The 
salts  of  this  metal  are  mostly  of  a  rose  color,  and  insoluble,  or 
nearly  so,  in  water.    They  are  of  no  practical  value. 

Osmium  (Os  99.6). 

This  metal  is  always  found  associated  with  iridium  in  pla- 
tinum, and  is  obtained  in  a  pulverulent  state.  It  dissolves, 
when  alone,  in  strong  nitric  acid' and  aqua  regia — in  both  cases 
forming  osmic  acid.  It  combines  with  oxygen  in  five  propor- 
tions:— 

Protoxide       .       .       .       .       .  =OsO. 

Sesquioxide     .....  =Os203. 

Binoxide.       .....  =Os02. 

Peroxide  =Os03. 
Osmic  acid      .       .       .       .       .  =OsO,. 

These  oxides  are  nearly  all  brown.  There  are  also  correspond- 
ing chlorides,  which  are  generally  colored. 

Ehodium  (E  52.2). 

This  is  another  metal  found  alloyed  with  platinum,  which 
it  resembles  in  appearance,  but  is  brittle  and  hard.  If  pure, 
it  is  not  acted  upon  by  any  of  the  acids,  but  when  alloyed  with 
another  metal,  as  with  platinum,  it  readily  dissolves  in  aqua 
regia.  Soda  precipitates  both  metals  from  this  solution ;  but 
the  platinum  precipitate  is  soluble  in  alcohol,  and  is  thus  easily 
separated.  The  rhodium  in  this  state  is  of  a  beautiful  rose 
color,  and  combines  with  oxygen  in  two  proportions: — 

Protoxide        .       .       .       .       .  =EO. 
Peroxide  ......       =  E203. 

The  protoxide  has  not  been  isolated ;  the  peroxide  is  a  black 
powder.  The  salts  are  all  less  or  more  colored,  and  generally 
give  colored  precipitates  with  reagents.  Ehodium  has  been 
introduced  into  the  arts  on  account  of  its  giving  great  hard- 
ness to  metals  alloyed  with  it.  It  is  used  for  tipping  metallic 
(gold  and  silver)  writing  pens,  &c. 
14 


4 


210 


LANTHANIUM. 


Lanthanium  (La  48). 

This  metal  has  been  but  recently  discovered  in  a  mineral 
from  which  cerium  is  obtained.  Its  oxide  has  a  brick-red  color, 
and  dissolves  ip  acids,  giving  red-colored  salts. 

Along  with  this  metal  another  has  been  detected  by  the  same 
discoverer ;  it  is  named  Didymium,  and  very  much  resembles 
Lanthanium  in  its  chemical  properties. 

Within  these  few  years,  discoveries  of  several  other  metals 
have  been  announced ;  these  are  all  of  course  rare,  and  their 
properties  have  not  yet  undergone  any  very  extensive  exami- 
nation.   Their  names  are 

Erbium — Niobium — Pelopium — Ruthenium — Terbium. 

Some  of  these  may  yet  be  found  to  be  peculiar  combinations  of 
other  known  metals,  but  until  that  is  proved,  we  must  look  upon 
them  as  metallic  elements. 

In  the  preceding  sketch  of  the  elements,  we  have  treated 
very  briefly  all  those  which  have  not  yet  had  any  practical  ap- 
plication to  the  art  of  dyeing,  and  also  those  that  are  rare  and 
expensive.  Of  those  elements,  we  have  noticed  merely  the 
features  and  reactions  which  seemed  to  us  best  calculated  to 
attract  attention,  or  which  might  suggest  experiments,  with  a 
view  to  their  application  in  the  trade.  And  although  many  of 
the  metallic  elements,  which  give  indications  of  available  pro- 
perties, are  at  present  too  rare  to  be  employed,  yet  we  know 
not  how  soon  the  rarest  of  them  may  be  discovered  in  abun- 
dance; and  it  is  a  law,  quite  as  certain  as  gravitation  itself,  that 
if  a  demand  be  created,  exertion  will  follow  to  satisfy  it.  When 
chromium  was  first  discovered,  it  was  considered  a  rare  metal, 
but,  as  the  demand  grew,  other  ores  were  found  to  contain  it  in 
great  abundance,  and  so  it  may  be  with  some  of  those  metals 
now  considered  the  most  rare  and  the  most  unlikely  ever  to  be- 
come abundant.    ^  q.  ~  Vb^^<jLi>4A*vvv  * 


I 


211 


TEXTILE  FIBRES. 

As  the  processes,  the  mordants,  and  the  coloring  substances 
employed  in  dyeing  often  vary  with  the  nature  of  the  fabric 
or  stuff  to  be  dyed,  it  is  necessary  to  examine  briefly  the  corn- 
position,  nature,  and  properties  of  the  textile  fibres. 

These  fibres  are  generally  divided  into  two  classes  :  the  vege- 
table,' and  the  animal. 

The  first  class,  among  quite  a  variety  of  substances,  com- 
prises cotton,  flax,  and  hemp,  which  are  mostly  composed  of 
lignine. 

The  second  class,  not  so  numerous,  contains  silk  and  wool. 

Cotton. — This  substance  (Gossypium)  forms  the  filaments 
which  envelope  the  seeds  of  plants  and  trees  belonging  to  the 
botanical  family  of  Malvaceae,  and  growing  in  many  parts  of 
the  globe,  in  Northern  and  Central  America,  Brazil,  Egypt, 
Persia,  India,  &c. 

There  are  a  great  many  varieties,  distinguished  by  the 
length  of  their  staple,  their  fineness,  and  their  color. 

Cotton  is  white,  yellow,  or  reddish.  The  composition  of  the 
coloring  matter  is  not  entirely  known;  it  is  associated  to  some 
pectine  and  resinous  substances,  which  can  be  removed  by 
treatment  with  diluted  alkaline  solutions.  The  long  staple 
cotton  is  generally  finer,  more  elastic,  and  stronger,  than  the 
short  staple. 

Viewed  under  the  microscope,  cotton  appears  like  a  tube, 
which  is  the  more  flattened  and  twisted  as  the  fruit  was  more 
ripe  at  the  time  of  the  gathering  of  the  crop.  Unripe  and 
desiccated  cotton  is  also  flattened,  but  the  tubes  appear  split 
throughout  their  length.  This  kind  of  cotton  is  sometimes 
called  "  dead  cotton." 

Flax. — This  plant  (Linum  usitatissimum),  of  annual  growth, 
had  its  birth  in  Central  Asia,  and  has  been  naturalized  in  near- 
ly every  civilized  country.  Several  varieties  are  cultivated, 
and  are  distinguished  by  the  difference  in  coarseness  of  their 
fibres.  The  finest  qualities  are  gathered  four  or  five  weeks  be- 
fore the  ripening  of  the  seeds. 

The  analysis  of  the  flax  plant  desiccated  at  212°  Fah.,  shows 
95  per  cent,  of  organic  matter,  and  5  per  cent,  of  mineral  sub- 
stances, composed  of  potassa,  soda,  lime,  and  phosphoric  acid. 
Irish  flax  contains  much  silica  ;  that  of  Holland  and  Belgium 
scarcely  any. 


212 


TEXTILE  FIBRES. 


Its  fibres  are  agglutinated  by  a  mixture  of  resin,  vegetable 
wax,  gum,  pectine,  sugar,  albuminoid  and  nitrogenized  sub- 
stances, &c,  which  it  is  necessary  to  remove  by  a  kind  of 
spontaneous  fermentation  in  water.  It  is  important  that  the 
water  should  be  free  from  calcareous  and  ferruginous  sub- 
stances. By  fermentation,  the  foreign  matters  are  destroyed 
and  dissolved,  with  the  evolution  of  ill-smelling  gases. 

This  process,  which  is  tedious  and  noxious,  if  made  in  the 
neighborhood  of  habitations,  can  be  effected  much  more  rapid- 
ly (in  48  hours)  in  vats  with  tepid  water.  There  is  also  an 
advantage  in  the  quality  and  quantity  of  the  products. 

The  fibre  of  flax  is  composed  of  a  series  of  hollow,  cylin- 
drical, and  rigid  tubes,  whose  surface  is  quite  smooth,  and 
shows  some  black  spots. 

Hemp. — This  plant  (Cannabis  sativa)  does  not  bear  on  the 
same  stem  the  male  and  female  flowers.  The  male  sterns  are 
slender, and  become  ripe  sooner  than  the  female  ones. 

There  is  a  great  analogy  (not  for  botanists,  however),  be- 
tween hemp  and  flax.  The  process  of  culture,  fermentation, 
and  mode  of  treatment  are  quite  the  same.  But  the  fibres  of 
hemp  are  twice  as  coarse  as  those  of  flax,  and  its  tubes  are 
accompanied  at  their  junction  with  small  filaments. 

Silk. — This  animal  fibre  is  the  fine  and  strong  thread  secre- 
ted by  the  mouth  of  the  silkworm  (bombix)  when  building  its 
cocoon.  The  silk  thread  is  formed  of  two  filaments  exuded 
from  two  orifices  near  the  mouth  of  the  worm,  and  which 
become  agglutinated  as  soon  as  formed. 

Silk,  viewed  under  the  microscope,  is  an  exceedingly  fine 
tube,  which  is,  not  twisted  like  cotton,  and  is  not  divided  into 
compartments  like  flax. 

The  exterior  of  the  silk  fibre  proper  is  covered  with  an 
organic  substance,  which  may  be  dissolved  by  an  alkaline  solu- 
tion, while  above  this  are  other  substances  soluble  in  water. 
This  kind  of  varnish  contains  nitrogenized  matters,  a  sort  of 
wax,  and  a  yellow  pigment. 

Silk  differs  from  wool  by  the  absence  of  sulphur;  and  from 
the  vegetable  fibres  because  it  contains  nitrogen. 

Wool,  or  the  fur  of  sheep,  goats,  &c,  appears  under  the 
microscope  like  a  series  of  thimbles,  inserted  one  into  another, 
and  covered  with  curved  filaments.  The  fibre  is  coarser,  and 
more  or  less  wiry  according  to  the  nature  of  the  sheep.  It 
contains  also  a  canal  filled  with  a  liquid,  which  is  sometimes 
colored. 

Wool  is  covered  with  a  great  quantity  of  fatty  substances, 
some  of  them  forming  a  kind  of  potassa  soap,  soluble  in  water, 
while  the  others  have  to  be  removed  by  alkaline  solution. 


/ 


TEXTILE  FIBRES. 


213 


Deprived  of  its  impurities,  wool  is  a  compound  of  oxygen,  hy- 
drogen, nitrogen,  and  sulphur. 

•  Generalities  on  Textile  Fibres— It  is  often  necessary 
to  distinguish  textile  fibres,  one  from  the  other;  we  now  give 
some  examples. 

A  boiling  solution  of  caustic  potassa,  into  which  threads  of 
cotton  and  flax  have  been  steeped  during  two  minutes,  gives  a 
dark  yellow  coloration  to  flax,  while  cotton  is  white  or  slightly 
yellow. 

Mr.  Mercer,  by  passing  cotton  fabrics  through  cold  and  con- 
centrated alkaline  solutions,  then  washing  in  water,  passing  into 
diluted  sulphuric  acid,  and  finally  rinsing,  obtained  tissues, 
which  had  contracted  in  every  direction,  and  were  much 
stronger  than  before.  At  the  same  time  they  absorbed  more 
coloring  matter  and  were  dyed  more  evenly. 

We  distinguish  wool  from  cotton,  flax,  and  hemp,  by  boiling 
a  sample  of  the  suspected  mixture  in  a  solution  of  caustic  soda, 
(8°  B.),  during  two  hours.  If  all  is  wool,  all  will  be  dissolved, 
the  vegetable  substances  resisting  the  operation. 

Nitric  acid  colors  wool  yellow,  after  exposure  of  a  few 
minutes  to  a  moderate  temperature;  cotton  remains  white. 

The  bichloride  of  tin,  with  the  help  of  heat,  will  blacken 
cotton  and  flax,  while  wool  is  not  affected. 

Boiling  and  weak  muriatic  acid  dissolves  cotton  easily,  and 
does  not  attack  wool. 

A  mixture  of  wool  and  silk  is  detected  by  a  solution  of 
oxide  of  lead  in  caustic  soda,  which  colors  the  wool  brown, 
and  has  no  action  on  the  silk. 

These  reactions  require  that  the  samples  should  not  be  dyed; 
if  they  are  colored,  it  will  be  necessary  to  remove  the  color 
by  successive  treatments  with  acids  and  alkalies. 

Cold  nitric  acid  dissolves  silk,  while  wool  remains  unaffected. 

Cotton,  flax,  and  hemp,  are  easily  soluble  in  a  cupro- 
ammoniacal  liquor,  made  by  placing  in  contact  with  the  air 
aqua  ammonia  and  copper  turnings,  and  which  appears  to  be 
a  basic  nitrate  of  copper  and  ammonia.* 

Textile  fibres  plunged  into  a  solution  of  alloxane,  then  wrung 
out  and  dried,  have  acquired  the  following  shades: — 

Wool — a  dark  red  purple  (amaranth); 

Silk — a  light  pink  yellow; 

Cotton  and  Flax — a  light  ,  yellow  tinge,  which  is  easily  re- 
moved by  washing. 

*  Silk  is  also  affected  by  this  solution,  but  more  slowly  than  the  vegetable 
fibres. 


214 


MORDANTS. 

If  the  various  coloring  matters  used  in  dyeing  had  an  affinity 
for  the  fibre  in  its  natural  state,  the  process  would  be  very  sim- 
ple ;  it  would  only  be  necessary  to  make  a  solution  of  the  dye- 
drug,  and  immerse  the  goods  in  it  to  insure  their  being  dyed. 
But  so  far  from  this  being  the  case,  if  we  except  indigo  and 
safflower,  there  is  scarcely  a  dyestuff  that  imparts  its  own  color 
to  goods;  nay,  the  greater  part  of  the  dye  drugs  used  have  so 
weak  an  affinity,  for  cotton  goods  especially,  that  they  impart 
no  color  sufficiently  permanent  to  deserve  the  name  of  a  dye. 
The  cause  of  this  is  obvious.  If,  for  example,  we  take  a  decoc- 
tion of  logwood,  the  coloring  matter  is  held  in  solution  by  the 
water ;  by  putting  a  quantity  of  cotton  into  this  solution  the 
fibres  become  filled  with  the  colored  solution,  but  if  the  cotton 
has  no  power  to  render  that  coloring  matter  insoluble  within 
its  fibres,  it  is  plain  that,  by  taking  out  the  cotton  and  putting 
it  into  water,  the  coloring  matter  within  it  will  be  diffused  in 
the  water ;  in  other  words,  the  dye  having  no  attraction  for  the 
fibre,  is  washed  out.  This  primary  want  of  affinity  makes  dye- 
ing sufficiently  intricate,  and  renders  it  more  dependent  upon 
science;  indeed,  it  is  only  by  the  nicest  arrangement  of  a  few 
chemical  laws,  that  the  dyer  is  enabled  to  turn  to  advantage 
the  various  coloring  matters  of  which  he  is  in  possession. 
When  the  dyer  finds  that  there  is  no  affinity  between  the  goods 
and  any  coloring  substance  which  is  put  into  his  possession,  he 
endeavors  to  find  a  third  substance,  which  has  a  mutual  attrac- 
tion for  the  cloth  and  coloring  matter,  so  that  by  combining 
this  substance  with  the  cloth,  and  then- passing  the  cloth  through 
the  dyeing  solution;  the  coloring  matter  combines  with  the  sub- 
stance which  is  upon  the  goods,  and  constitutes  a  dye.  This 
third  substance  used,  which  acts  as  a  mediator,  combining  two 
inimical  bodies,  is  termed  a  mordant,  from  the  French  mordre, 
to  bite,  from  an  idea  which  the  old  dyers  had  that  these  sub- 
stances bit  or  opened  a  passage  into  the  fibres  of  the  cloth, 
giving  access  to  the  color.  And  although  the  theory  of  their 
action  is  now  changed,  the  term  is  still  continued,  and  perhaps 
farther  investigation  will  prove  the  term  applicable. 

All  the  mordants,  with  one  or  two  exceptions,  are  found 
among  the  metallic  oxides.  It  may  be  supposed  from  this  that 
as  metals  are  the  most  numerous  class  of  elements,  mordants 
are  also  very  numerous ;  it  is  not  so,  however.    In  order  that 


MORDANTS. 


215 


the  substance  may  act  as  a  mordant,  it  must  possess  certain 
properties  ;  it  must  have  an  attraction  for  the  coloring  matter, 
so  as  to  form  with  it  an  insoluble  colored  compound;  and  it 
must  be  held  easily  in  solution.  It  may  also  have  an  affinity 
for  the  fibre,  a  tendency  to  unite  with  it ;  but  this  property  is 
not  essentially  necessary  ;  only  the  first  two  properties  are  so, 
and  they  limit  the  mordants  almost  wholly  to  what  are  termed 
the  insoluble  bases — that  is,  substances  which  are  not  by  them- 
selves soluble  in  water. 

The  bases  or  oxides  which  are  in  general  use  as  mordants, 
and  which  appear  to  succeed  best,  are  alumina,  and  the  oxides 
of  tift  and  iron  ;  the  first  two  are  colorless,  and  the  peroxide  of 
the  latter  is  a  light  brown,  and  imparts  to  white  goods  a  buff  or 
nankeen  color,  which  in  many  cases  affects  to  a  considerable 
extent  the  color  of  the  cloth,  a  circumstance  which  must  also 
be  attended  to  by  the  dyer.  Indeed,  the  principal  part  of  all 
dyeing  operations  is  the  proper  choice  and  application  of  mor- 
dants ;  there  being  a  chemical  union  between  them  and  the 
coloring  matter  a  new  substance  is  formed,  not  only  differing 
in  properties,  but  differing  in  color,  from  any  of  the  originals; 
consequently  a  very  little  alteration  in  the  strength  or  quality  of 
a  mordant  gives  a  decided  alteration  in  the  shade  of  color. 
However,  it  gives  the  dyer  a  much  wider  field  for  variety  of 
shades;  and  at  the  same  time  a  less  number  of  coloring  sub- 
stances are  required;  as,  for  example,  logwood  alone  gives  no 
color  to  cotton  worthy  the  name  of  a  dye  ;  yet  by  the  judicious 
application  of  a  few  different  kinds  of  mordants,  all  the  shades, 
from  a  French  white  to  a  violet,  from  a  lavender  to  a  purple, 
from  a  blue  to  a  lilac,  and  from  a  slate  to  a  black,  are  obtained 
from  this  substance. 

Before  any  chemical  union  takes  place  between  bodies,  they 
must  not  only  be  in  contact,  but  they  must  be  reduced  to  their 
ultimate  molecules  ;  hence,  mordants  that  are  insoluble  of  them: 
selves  must  be  dissolved  in  some  appropriate  menstrua  before 
their  particles  can  enter  the  fibres  of  the  goods,  or  combine  with 
the  coloring  matter.  In  doing  this,  the- dyer  must  attend  to 
the  degree  of  affinity  between  the  solvent  and  the  mordant,  to 
determine  what  force  it  will  exert  against  the  mordant  com- 
bining with  the  fibres  of  the  cloth,  should  there  exist  an  affinity 
between  them,  otherwise  a  powerful  mordant  may  be  weakened 
by  the  attraction  of  its  solvent ;  as,  for  example,  common  alum, 
even  though  much  concentrated,  is  but  a  weak  mordant  for 
cotton  goods,  owing  to  the  great  attraction  between  the  sul- 
phuric acid  and  the  alumina.  But  if  acetic  acid,  which  has 
comparatively  a  weak  affinity  for  the  alumina,  be  substituted 
for  the  sulphuric  acid,  it  becomes  a  very  powerful  mordant. 


216 


MORDANTS. 


From  these  things  having  to  be  attended  to,  the  dyer  has  many 
beautiful  illustrations  of  the  relative  attraction  of  different  sub- 
stances for  each  other.    In  some  cases,  the  attractions  are  so 
nicely  balanced  that  the  mordant  and  coloring  matter  may  be 
kept  mixed,  and  the  goods,  when  immersed  in  this  solution, 
having  a  kind  of  reciprocal  affinity,  only  receive  their  share, 
and  do  not  extract  the  coloring  matter  from  the  solvent,  but  the 
depth  of  color  upon  the  cloth  corresponds  with  the  color  of  the 
solution.    In  other  cases,  the  attraction  between  the  mordant 
and  coloring  matter  is  so  powerful,  that,  if  the  least  quantity  of 
the  mordant  solution  be  upon  the  cloth  when  put  into  the  dye, 
it  seizes  the  coloring  matter,  which  is  instantly  precipitated  or 
rendered  insoluble,  and  therefore  unfit  to  combine  with  the 
goods,  and  what  coloring  matter  may  have  combined  with  the 
cloth  before  being  all  precipitated,  will  be  uneven  ;  that  is,  the 
resulting  color  will  be  light  and  dark.    From  these  circum- 
stances, the  close  alliance  of  the  art  of  dyeing  to  the  science  of 
chemistry,  is  evident;  but  an  individual  from  experience  may 
know  these  effects,  and,  though  ignorant  of  the  cause,  may  often 
guard  against  their  consequences  ;  knowledge,  however,  pro- 
cured only  by  routine  practice,  is  purchased  at  a  very  great  cost, 
and  attended  with  many  unpleasant  circumstances.    In  cases 
where  the  base  has  no  affinity  for  the  fibre,  there  exists  the  same 
difficulty  as  with  the  coloring  matter,  the  fibre  being  filled  with 
the  solution  of  the  base  ;  should  the  goods  so  filled  be  passed 
through  water,  the  base  will  be  washed  out ;  and  should  they 
be  put  into  the  dyeing  solution,  immediately  and  directly  a  great 
quantity  of  the  coloring  matter  will  be  precipitated  upon  the 
fibre,  not  within  it,  and  will  thus  be  left  merely  adhering  to  the 
surface,  and,  when  dry,  much  of  it  will  of  course  come  off  as 
dust,  which  is  so  much  loss.    Thus,  the  salts  of  lead  have  little 
or  no  affinity  for  the  fibre,  and  if  cotton,  impregnated  with 
nitrate  or  acetate  of  lead,  be  washed  several  times,  nearly  the 
whole  lead  is  dissolved  out.    If  put  through  the  bichromate  of 
potash  solution  directly  from  the  lead,  a  great  quantity  of 
chromate  of  lead  will  fall  to  the  bottom  of  the  tub,  and  be  lost ; 
but  by  passing  the  goods  from  the  lead  solution  through  a  little 
lime-water,  the  lime  takes  away  the  acid,  the  lead  is  fixed  with- 
in the  fibre  as  an  oxide,  and  when  put  into  the  chrome  solu- 
tion, combines  with  the  chromic  acid,  and  no  chromate  of  lead 
is  precipitated.    Nevertheless,  there  are  colors  that  require  a 
little  of  the  free  mordant  to  be  added  to  bring  out  the  color. 
Thus,  a  piece  of  cotton  passed  through  red  spirits,  and  then 
well  washed  in  water,  will  not  lose  all  the  tin.    Let  the  cotton 
be  put  into  a  solution  of  logwood;  this  will  combine  with  the 
base  or  oxide  of  tin,  and  leave  the  water  nearly  colorless,  giving 


MORDANTS. 


217 


a  reddish-brown  color  to  the  goods,  very  imperfect,  indeed,  and 
not  suitable  as  a  dye  ;  but  by  adding  a  small  quantity  of  spirits 
to  this  exhausted  water,  and  then  immersing  the  dyed  cotton 
again,  instantly  the  true  violet  or  purple  color  is  brought  up. 
The  substances  thus  added  to  the  colored  liquor  to  change  and 
fix  the  colors  are  termed  alterants,  and  the  operation,  in  the 
language  of  the  dye-house,  raising,  because  it  brightens  the 
color.  Alterants  and  mordants  are  often  spoken  of  as  two 
distinct  substances  ;  but  the  only  distinction  is  in  the  mode  of 
applying  them.  In  some  instances  distinct  substances  are  used. 
In  the  process  detailed  above,  a  little  alum  would  do  as  well 
as  the  tin  :  or  if  a  particular  bluish  shade  were  wanted,  a  little 
pyrolignite  of  alumina  ;  but  in  almost  all  cases  the  mordant 
may  also  be  used  as  the  alterant.  This  shows  that  in  some  in- 
stances the  dye  may  require  some  of  the  acid  in  the  salt,  which 
constituted  the  mordant,  to  bring  it  out;  and  must  be  applied 
after  the  color  is  fixed.  If  in  the  above  operation  the  cloth 
had  been  passed  through  the  hot  logwood  solution  directly  from 
the  spirit  tub,,  the  logwood  would  have  been  precipitated  ;  and, 
except  the  decoction  had  been  very  strong,  the  color  upon  the 
fibre  would  have  been  weak  and  unequal.  Other  matters  are 
often  added  as  a  sort  of  alterant  in  some  colors,  not  to  effect 
the  required  change  of  the  color,  but  to  take  up  some  sub- 
stance that  may  have  a  tendency  to  retain  the  coloring  matter, 
and  prevent  its  uniting  with  the  mordant.  Thus  it  may  be 
necessary  with  lead  mordants,  where  the  acid  of  the  lead  is  taken 
away,  to  add  some  acid  to  the  chrome  solution,  to  combine  with 
the  potash,  in  order  to  liberate  the  chromic  acid,  and  allow  it 
more  freely  to  take  the  lead.  This  is  particularly  the  case  with 
Prussian  blue.  If  the  goods  are  washed  from  the  nitrate  of 
iron  solution,  or  passed  through  an  alkali,  a  little  acid  must  be 
added  to  the  Prussiate  solution,  to  take  the  potash  and  liberate 
the  prussic  acid. 

It  is  with  the  vegetable  coloring  matters,  however,  that  the 
greatest  attention  must  be  paid  to  the  many  conditions  and 
properties  of  mordants;  some  of  these  may  be  shortly  noticed. 

The  mordant,  or  solvent  of  the  base  constituting  the  mordant, 
should  not  be  capable  of  injuring  or  destroying  immediately, 
or  by  prolonged  action,  either  the  coloring  matter  or  the  fabric. 
Thus  acids  do  not  serve  as  mordants,  as  they  generally  either 
destroy  the  fabric  or  the  coloring  matter;  and  in  cases  where 
destructive  acids  are  used,  care  has  to  be  taken  that  they  are 
washed  off  or  neutralized  before  they  have  had  time  to  act  upon 
the  tissue  or  upon  the  color.  The  principle  here  stated  opens 
a  very  wide  field  of  inquiry,  embracing  the  whole  range  of 
dyeing  operations.    The  action  of  bases  upon  colors,  and  the 


218 


MORDANTS. 


condition  of  those  best  adapted  to  give  beauty  and  permanency, 
are  most  important  subjects,  and  deserve  that  we  should  here 
consider  them  a  little  in  detail. 

1st.  The  base  being  insoluble  in  water,  has  to  be  rendered 
soluble  by  combining  it  with  an  acid,  so  as  to  allow  the  base 
to  combine  with  the  coloring  matter.  What  becomes  of  that 
acid  which  holds  the  base  in  solution  when  the  coloring  matter 
combines  with  the  base?  Will  it  act  upon  the  color  formed? 
We  have  already  discussed  this  point,  as  regards  lead  and  chrome 
(page  190) ;  we  will  now  take  another  color,  which,  although 
strictly  speaking  it  does  not  embrace  the  action  of  a  mordant, 
will  serve  very  well  to  illustrate  the  point  of  inquiry.  Indigo 
is  dissolved  in  strong  sulphuric  acid,  and  is  used  in  this  state 
for  dyeing  green  upon  light  cotton  cloths.  The  goods  are  first 
dyed  yellow  by  bark  or  fustic,  and  then  dyed  blue  by  means 
of  sulphate  of  indigo,  which  gives  green.  Now,  were  the  yellow 
dye  passed  through  the  sulphate  of  indigo,  the  acid  would 
destroy  the  yellow,  and  spoil  the  color ;  the  acid  has,  therefore, 
to  be  neutralized,  and  soda  or  potash  is  employed  for  this 
purpose,  according  to  ordinary  practice.  We  have  then  the 
sulphate  of  the  alkali  held  in  solution  writh  the  indigo;  and, 
although  the  acid  will  not  now  destroy  the  yellow,  there  is 
another  consideration,  namely,  the  effect  of  this  sulphate  of  the 
alkali  upon  the  color ;  and  if  there  be  an  effect,  it  becomes  a 
question  how  to  avoid  it.  Thus  every  circumstance  produces 
a  new  feature,  and  should  be  fully  studied. 

2d.  We  must  consider  the  nature  and  properties  of  the  base 
constituting  the  mordant,  and  its  reaction  upon  the  coloring 
matter,  both  when  combining,  and  afterwards  under  exposure. 
Thus  we  have  stated,  when  treating  of  the  oxides  of  iron  and 
tin,  that  these  substances,  under  various  circumstances,  are  un- 
stable, the  protoxide  having  a  strong  attraction  for  oxygen, 
and  the  peroxide,  when  in  contact  with  organic  matters,  readily 
yielding  oxygen. 

In  one  or  other  of  these  conditions,  these  bases  combine  with 
the  coloring  matter.  How,  then,  will  the  above  properties 
affect  the  compound  ?  The  action  of  the  peroxide  in  contact 
with  organic  matters,  seems  to  supply  an  answer  to  the  ques- 
tion, because  in  all  cases  in  which  peroxides  give  up  their 
oxygen  to  the  organic  coloring  matter  and  become  protoxides, 
the  protoxide  is  the  proper  condition  of  applying  the  mordant. 
On  any  other  supposition  it  would  be  necessary  to  prove  that, 
when  peroxide  is  applied,  the  giving  up  of  the  oxygen  pro- 
duces a  reaction  favorable  to  the  resulting  color  ;  but  this  is 
seldom  if  ever  the  case.  The  reaction  of  the  peroxide  is  gene- 
rally the  combination  of  a  part  of  the  oxygen  with  the  hydro- 


MORDANTS. 


219 


gen  of  the  coloring  matter,  which  thus  becomes  partially  de- 
composed. This  will  be  seen  by  attempting  to  dye  common 
black  with  a  persalt  instead  of  a  protosalt  of  iron ;  or,  by 
adding  a  persalt  of  iron  to  a  solution  of  galls  or  sumach,  and 
allowing  them  to  stand,  the  color  will  be  greatly  deteriorated. 
Supposing  cloth  from  sumach  put  into  a  solution  of  persul- 
phate of  iron,  there  will  be  a  decomposition  ;  the  persulphate 
being  three  acid  and  Voiron,  some  of  the  hydrogen  of  the  vege- 
table color  will  produce  one  proportion  of  free  acid  by  the  re- 
duction of  the  per  to  the  proto  sulphate.  When  peroxide  of 
iron  is  fixed  upon  the  cloth  free  from  acid,  and  put  into  the 
colorihg  matter,  water  is  formed  by  the  oxygen  of  the  peroxide 
and  the  hydrogen  of  the  coloring  matter.    We  then  have — 


So  that  one-third  of  the  coloring  matter  will  be  destroyed,  and 
a  more  imperfect  dye  will  result,  as  will  be  more  fully  illus- 
trated when  we  come  to  describe  the  composition  of  the  vege- 
table dyes. 

It  is  this  principle  which  prevents  the  use  of  many  oxides 
of  metals  that  might  otherwise  be  valuable,  such  as  oxide  of 
silver,  mercury,  &c,  which  are  easily  reduced  by  organic 
matters.  When  any  of  these  bases  combine  with  coloring 
matters  as  mordants,  they  are  gradually  reduced,  and  pass 
into  the  metallic  state,  the  oxygen  taking  the  hydrogen  or  the 
carbon  of  the  coloring  matter,  and  thus  the  color  fades  away. 
Still  this  property  of  giving  up  oxygen  is  often  of  great  value 
in  other  operations,  as  in  working  with  substances  that  require 
oxidation  to  give  a  color,  as  in  the  case  of  catechu ;  salts  of 
silver,  mercury,  &c,  would  serve  the  purposes  for  which  cop- 
per salts  are  at  present  applied  to  this  dye-drug;  whereas  per- 
salts  of  iron  cannot  be  used  with  this  substance  for  oxygen- 
izing purposes,  as  its  protosalt  blackens  the  tannin  of  the 
catechu,  and  affects  the  production  of  other  shades  of  color  ; 
but  where  modified  tints  are  required,  iron  furnishes  the 
means  of  obtaining  them  to  a  great  extent.  Thus,  by  a  care- 
ful study  of  the  conditions  of  the  mordants,  their  relations  to 
the  coloring  matter,  the  reactions  that  will  take  place  under 
all  the  varied  circumstances  of  application,  and  what  kind  of 
reaction  is  required  to  obtain  the  results  sought,  the  dyer  will 
find  his  trade  easy,  interesting,  and  pleasant.    When  the  mind 


Peroxide  .  .  .  .  <{  0 
0 

.0 


Hydrogen 


220 


MORDANTS. 


guides  the  hand,  labor  ceases  to  be  felt  either  as  a  curse  or 
degradation. 

In  connection  with  mordants,  Dr.  Bancroft,  in  his  work  on 
the  Philosophy  of  Permanent  Colors,  arranges  all  colors  in  two 
classes.    He  says  : — 

"To  me,  coloring  matters  seem  to  fall  naturally  under  two 
general  classes.  The  first  including  those  matters  which,  when 
put  into  a  state  of  solution,  may  be  fixed  with  all  the  perma- 
nency of  which  they  are  susceptible,  and  made  fully  to  exhibit 
their  colors  in  or  upon  the  dyed  substance,  without  the  inter- 
position of  any  earthy  or  metallic  basis.  The  colors  of  the 
first  class  I  shall  call  substantive,  as  denoting  a  thing  solid,  by 
or  depending  only  on  itself;  and  colors  of  the  second  class  I 
shall  call  adjective,  as  implying  that  their  lustre  and  permanency 
are  acquired  by  their  being  adjected  upon  a  suitable  basis. 

"Earthy  and  metallic  substances,  when  thus  interposed, 
serve  not  only  as  a  bond  of  union  between  the  coloring  mat- 
ter and  the  dyed  substance,  but  they  also  modify  as  well  as 
fix  the  color.  Some  of  them,  particularly  the  oxide  of  tin 
and  the  earth  of  alum,  exalting  and  giving  lustre  to  most  of 
the  coloring  matters  with  which  they  are  united ;.  whilst 
others,  and  especially  the  oxide  of  iron,  blacken  some,  and 
darken  almost  all  such  matters,  if  made  to  combine  with 
them."* 

This  clear  definition  will  remove  many  erroneous  impressions 
of  the  meaning  of  these  terms,  adjective  and  substantive.  We 
have  often  heard  an  adjective  color  defined  as  one  that  required 
to  be  previously  mordanted;  but  this  definition  is  ambiguous, 
and  seems  to  ground  the  distinction  more  upon  the  mode  of 
dyeing  than  upon  the  nature  of  the  color.  Thus,  by  passing  a 
piece  of  cotton  through  alum,  and  then  through  a  solution  of 
logwood,  we  produce  an  adjective  color,  having  been  previously 
mordanted ;  but  if  the  solutions  of  the  alum  and  logwood  be 
mixed  together,  and  the  piece  be  passed  through  this  mixture, 
the  same  color  is  produced.  Yet,  by  the  above  definition,  it 
would  be  a  substantive  color,  not  being  previously  mordanted, 
and  not  because  the  color  produced  is  neither  that  of  the  log- 
wood nor  of  the  alum,  but  of  the  compound  formed  between 
them.  Again,  if  we  pass  a  piece  of  cotton  through  a  solution 
of  copperas,  and  then  through  lime-water,  there  is  first  produced 
a  light-greenish  color,  which,  by  exposure  to  the  air,  becomes 
nankeen  or  buff;  and  notwithstanding  its  thus  taking  two 
operations,  equivalent  to  mordanting  and  dyeing,  the  color  pro- 
duced is  substantive,  being  the  pure  peroxide  of  iron  fixed 


*  Bancroft  on  Dyeing,  vol.  i.  page  118.  1813. 


MORDANTS.  ;       v  221 

■<y.      ft  •/ 

within  the  fibre.  Another  fallacy,  we  have  often  heard  of 
identifying  substantive  and  adjective  with  fast  :  f^tjitive. 
The  impropriety  of  this  application  of  the  term  is  show-ii-  by 
simply  referring  to  the  two  colors,  indigo  blue  and  safflower 
pink ;  both  are  eminently  substantive,  yet  the  one  is  fast  and 
the  other  fugitive. 

The  property  which  the  fibre  possesses  of  fixing  portions  of 
the  dyestuff  within  its  pores,  will  have  to  be  often  referred  to, 
as  ijb  bears  a  very  important  relation  to  mordants.  Astringent 
substances,  in  combining  with  the  fibres  of  cotton  goods,  have 
a  strong  relation  to  this  action.  A  piece  of  cotton,  put  into  a 
hot  solution  of  sumach,  and  remaining  in  it  until  cool,  there  is 
a  quantity  of  the  astringent  principle  fixed  upon  the  fibre, 
which  no  washing  will  remove.  We  have  seen  goods  thus 
treated  passed  afterwards  through  all  the  regular  operations  of 
bleaching,  and  still  retaining  so  much  of  these  substances  as 
was  sufficient  to  impart  a  black  tint  on  passing  them  through 
protosulphate  of  iron.  Hence  the  astringent  matters  in  many 
vegetable  dyes  act  a  very  important  part  in  the  dyeing  opera- 
tions. Whether  such  substances  as  galls  and  sumach,  which 
are  used  only  for  their  astringent  principle,  may  be  termed 
mordants,  is  a  question  we  need  not  discuss;  but  they  are 
essentially  necessary  for  fixing  within  the  fibre  such  quantities 
of  the  metallic  base  or  mordant  as  are  required  to  give  depth 
and  permanency  to  the  color ;  and  as  these  astringent  matters 
produce  tints  with  the  bases,  they  give  us  a  wider  scope  for 
variety  of  color.  Thus,  if  we  pass  a  piece  of  cotton  through 
a  solution  of  protochloride  of  tin,  and  then  wash  it  in  water, 
we  will  have  a  great  quantity  of  oxide  of  tin  fixed  within  the 
fibre  by  the  operation  of  washing  (page  177);  and  by  passing 
this  cloth  through  a  decoction  of  Brazil-wood,  and  then  raising 
with  a  little  spirits,  there  is  a  fine,  though  not  very  permanent, 
rose-red  produced.  If  we  pass  the  cotton  through  bichloride 
of  tin,  and  then  wash,  there  is  little  of  oxide  of  tin  fixed ;  for 
the  bichloride  is  not  decomposed,  as  the  protochloride  is,  by 
water.  If,  then,  it  be  passed  through  the  Brazil-wood  in  the 
same  manner  as  the  other,  a  color  of  less  depth  is  produced; 
but  if  the  cloth  be  previously  steeped  in  sumach,  and  be  then 
passed  through  the  tin  solution,  even  the  bichloride,  the  astrin- 
gent principle  of  the  sumach  combines  with  the  tin,  and  forms 
an  insoluble  compound  ;  and  there  is  thus  fixed  a  great  quantity 
of  the  metallic  base,  which  gives  the  color  with  the  Brazil-wood, 
so  that  when  immersed  into  the  wood  decoction,  there  is  ob- 
tained a  color  of  great  depth  and  permanency.  But  the  com- 
pound of  tin  and  sumach  gives  a  yellow;  thus,  therefore, 
peculiar  tints  of  the  color  are  obtained,  and  instead  of  having 


222 


MORDANTS. 


a  rose  color,  a  deep  rich  red,  between  rose  and  scarlet,  is  pro- 
duced. Thus  sumach,  galls,  &c,  are  extensively  used  in  con- 
nection with  metallic  bases,  to  fix,  modify,  and  impart  depth 
to  colors  for  which  these  bases  are  applied.  The  nature  of 
these  astringent  substances  will  be  given  under  the  distinctive 
names  of  the  matters  which  contain  them. 

The  strong  attraction  which  animal  fabrics,  as  silks  and 
woollens,  have  for  coloring  matters  is  well  known,  and  makes 
the  dyeing  of  these  matters  more  simple  than  that  of  cotton. 
The  mordants  used  are  often  of  a  class  that  does  not  act  the 
part  of  mordants  in  cotton.  From  this  cause,  means  were 
sought  to  impart  to  cotton  something  of  the  property  of  animal 
tissues.  Thus,  in  analyzing  a  piece  of  silk,  there  were  found : — 

Composition  of  Neapolitan  silk    .  .   


Fibres  of  silk   53.37 

Gelatin   20.66 

Albumen   24.43 

Cerin   1.39 

Fat  and  resin    .10 

Coloring  matter   .05 


100.00 

It  was  considered  that,  in  all  probability,  the  substances  giving 
the  property  to  silk  to  imbibe  and  fix  colors  more  easily  than 
cotton,  were  such  matters  as  albumen,  &c,  which  might  be 
imparted  artificially.  This  led  to  the  new  process  of  animal- 
izing  cotton,  as  it  is  termed.  Upon  this  subject  we  extract 
from  the  Chemical  Gazette,  vol.  viii.  page  384,  an  excellent 
article,  translated  from  the  Journ.  de  Chim.  et  de  Pharm.,  vol. 
xvii.  page  271 : — 

"  When  an  egg  is  boiled  in  a  color-bath,  the  color  immedi- 
ately fixes  itself  to  the  shell.  Egg-shells  contain,  like  bones, 
an  organic  tissue  and  mineral  salts.  If  it  is  attempted  to  dye 
these  mineral  salts — the  phosphate  or  carbonate  of  lime — sepa- 
rately, it  fails,  and,  therefore,  neither  of  these  salts  can  be 
regarded  as  the  mordant.  If,  on  the  contrary,  it  is  attempted 
to  color*  the  organic  tissue  of  egg-shells  or  of  bones,  this  im- 
mediately becomes  dyed ;  hence  it  follows  that  the  organic 
matter  of  the  bones  and  egg-shells  is  the  mordant. 

"Now,  in  the  same  manner  as  mineral  mordants  have  hither- 
to been  employed  to  fix  coloring  matters  upon  cotton,  organic 
mordants  may  be  used,  and  Broquette  has  already  employed 
casein  for  this  purpose.  The  coating  of  vegetable  fibres  with 
animal  substances  was  first  carried  out  by  M.  Hausmann,  as 


MORDANTS. 


223 


observed  by  M.  Barreswil,  in  this  article;  but  is  said  never  to 
have  attained  to  any  importance.  The  casein  must,  of  course, 
be  first  dissolved,  in  order  that  the  tissues  may  be  permeated 
by  the  solution,  but  it  must  then  be  rendered  insoluble  in  the 
tissues.  Now  it  has  been  shown  by  Braconnot  that  casein 
furnishes  a  soluble  compound  with  ammonia,  which  is  again 
decomposed  by  boiling.  Broquette,  therefore,  impregnates  the 
goods  with  a  solution  of  casein  in  ammonia,  then  heats  them 
to  expel  the  ammonia,  upon  which  the  casein  remains  in  an 
insoluble  state  in  the  tissues. 

"  Cotton  goods,  after  this  treatment,  are  saturated  with  ani- 
mal matter,  and  may  now  be  dyed  in  the  same  color-baths  as 
those  used  for  woollen  tissues. 

"Frequently  the  dyes  are  alkaline;  they  then  dissolve  the 
casein,  instead  of  being  fixed  by  it.  But  since  Bachelier  used 
as  a  cement  a  mixture  of  lime  and  casein,  it  is  known  that 
this  mixture  hardens  and  becomes  fixed.  Broquette  therefore 
employs  the  caseine  sometimes  with  lime  alone,  sometimes 
with  ammonia  and  lime  together,  and  saturates  the  goods  with 
this  caseate  of  lime,  which  soon  sets  in  a  warm  atmosphere, 
and  then  resists  the  alkalies  and  rinsing  with  alkaline  liquids. 

"By  this  treatment  the  cotton  acquires  a  peculiar  stiffness; 
so  that,  although  its  capacity  for  dyes  has  become  nearly  equal 
to  that  of  wool,  it  is  far  behind  the  latter,  owing  to  want  of 
lustre.  But  this  evil  can  also  be  remedied  by  mixing  the 
mordant  with  oil.  Oil,  casein,  and  lime,  form  a  mordant 
which  fixes  the  colors  with  a  perfectly  remarkable  lustre. 

"When  the  goods  to  be  dyed  consist  of  wool  and  cotton,  a 
different  plan  has  to  be  followed;  the  mordant  in  this  case  is 
not  adapted  for  the  two  materials;  the  wool  is  deprived  of  its 
natural  lustre,  and  the  cotton  tissues  are  not  sufficiently  pene- 
trated. For  such  goods  Broquette  employs  the  mordant  be- 
fore the  weaving ;  it  is  applied  to  the  cotton  in  the  spinning, 
when  it  can  afterwards  be  woven  and  bleached  like  wool,  with- 
out the  mordant  experiencing  any  injury.  When  threads  thus 
prepared  are  woven,  the  tissues  can  be  dyed  just  like  woollen 
stuffs,  without  further  treatment. 

"By  means  of  the  solution  of  caseate  of  lime,  mineral  colors 
which  are  insoluble  in  water  can  be  adapted  to  the  dyeing  of 
stuffs;  they  are  mixed  in  a  state  of  very  fine  powder  with  the 
solution.  These  liquid  colors,  which  can  be  prepared,  for 
instance,  with  ultramarine,  ochre,  &c,  can  again  be  removed 
with  water,  "unless  they  have  been  dried;  but  as  soon  as  they 
coagulate,  they  adhere  firmly  to  the  tissues  inclosing  the  color- 
ing principle. 

"A  farther  application  of  the  mordant  of  casein,  oil,  and 


224 


MORDANTS. 


lime,  is  in  the  printing  of  stuffs:  in  this  case  we  are  not  limited 
merely  to  mineral  colors,  which  by  its  aid  may  be  fixed  upon 
the  goods,  but  the  numerous  vegetable  colors  may  be  likewise 
very  well  applied,  by  first  converting  them  into  lakes  by  means 
of  alumina  or  protoxide  of  tin,  and  then  using  these  lakes  in 
the  same  manner  as  the  powdered  mineral  colors.  After  being 
printed,  the  goods  are  wrapped  in  moist  linen,  and  left  for 
about  half  an  hour  in  the  moist  vapor  in  a  warm  atmosphere. 
Daring  this  time  the  impressed  color  does  not  dry  superfi- 
cially, but  is  absorbed  into  the  interior  of  the  fibres,  and  is  then 
completely  fixed  in  the  subsequent  drying. 

u  This  new  method  of  mordanting  has  already  had  consider- 
able influence  upon  several  pigments,  for  instance  upon  archil, 
which  has  only  been  used  for  dyeing  exceptionally;  according 
to  Broquette's  process,  some  very  beautiful  colors  are  obtained 
from  it,  modifications  of  the  peculiar  color  of  the  archil  by 
lime. 

"It  will  be  evident,  from  what  has  been  above  stated,  that 
in  this  process  of  dyeing  it  is  requisite  to  pass  the  goods 
through  a  lime-bath,  which  will  not  do  for  many  dyes,  as  the 
colors  have  their  tints  altered  by  such  treatment.  In  such 
cases  magnesia  is  to  be  substituted  for  the  lime. 

"  When  goods  are  printed  with  the  mineral  colors  or  lakes, 
according  to  the  above  process,  very  full  colors  are  obtained, 
which,  in  the  case  of  many  patterns,  is  not  desirable.  To 
bring  out  the  shades  and  half-colors  in  the  full-colored  impres- 
sions, the  printed  goods  are  placed  with  their  colored  surface 
upon  an  absorbing  ground,  cotton  stuff,  and  the  forms  pressed 
on  the  back.  The  printed  cotton  pressed  upon  the  absorbing 
surface  is  deprived  of  some  of  its  color,  and  numerous  patterns 
can  be  produced  in  this  manner." 

The  preparation  of  the  salts  which  constitute  mordants  has 
been  given  under  the  particular  element  constituting  the  base 
of  the  salt ;  but  we  mentioned  that  different  methods  of  pre- 
paring such  salts  are  practised  by  different  dyers,  every  one 
preferring  his  own  method,  from  some  real  or  supposed  pecu- 
liarity or  advantage  it  possesses;  although  in  some  cases  this 
difference  is  difficult  to  appreciate,  both  because  the  acids  used 
are  not  regularly  tested,  and  also  because  it  is  a  common  cus- 
tom to  take  the  acids  by  measure;  so  that  when  a  dyer  says 
he  prefers  4  to  1,  he  as  often  means  4  jugs  as  4  lbs.  Now, 
nitric  acid  having  a  specific  gravity  much  above  that  of  hydro- 
chloric acid,  recipes,  in  which  the  proportions  are  given  in 
volume,  will  of  necessity  differ  very  essentially  from  those  in 
which  they  are  given  in  weight. 

Bed  Spirits. — These  are  named  from  being  used  in  dyeing 


MORDANTS. 


225 


red  by  means  of  Brazil  and  other  red  woods.  They  are  some- 
times termed  nitromuriate  of  tin,  from  being  prepared  by  a 
mixture  of  these  acids.    Mix  together 

1  lb.  Nitric  acid, 

3  lbs.  Hydrochloric  acid. 

Add  feathered  tin,  in  small  quantities  at  a  time,  until  the  acid 
ceases  to  dissolve  more  ;  pour  off  the  clear,  and  preserve  in  a 
dark  cool  place.    This  is  a  spirit  for  a  deep,  heavy  red. 
If  a  red  of  a  bluer  or  crimson  hue  be  required,  then — 

1  lb.  Nitric  acid, 

5  lbs.  Hydrochloric  acid, 

dissolving  the  tin  as  above,  will  be  a  better  quality  of  mor- 
dant. The  proportion  of  nitric  acid  gives  brown  or  depth  to 
the  red  ;  but  some  sorts  of  woods  contain  more  of  the  yellow 
or  browning  principle  than  others.  Attention  ought  to  be 
paid  to  this  circumstance,  and  to  prepare  the  spirits  suitably 
to  the  character  of  the  wood  which  is  to  be  used  as  the  dye. 
This  difference  of  tints  is  occasionally  regulated  by  the  quan- 
tity of  tin  dissolved;  hence  some  dyers  give  a  definite  quantity 
of  tin,  generally  from  2  ounces  to  2 J  ounces  to  the  pound  of 
mixed  acids;  this  is,  indeed,  not  far  from  what  is  generally 
dissolved  when  tin  is  added  to  saturate  the  acid.  Whichever 
method  is  adopted,  it  is  necessary  that  there  should  always  be 
a  knowledge  of  the  quantity  of  tin  which  the  spirit  contains ; 
and,  moreover,  as  this  is  commonly  prepared  in  the  open  air, 
the  quantity  of  tin  dissolved  will  depend  somewhat  on  the 
season  of  the  year,  on  account  of  the  influence  which  tempera- 
ture has  on  the  action  of  the  acid.  When  red  spirits  are  used 
with  logwood,  the  influence  of  the  proportions  of  nitric  acid  is 
very  apparent,  causing  the  purples,  or  such  colors  dyed,  to  dry 
brownish — a  result  which  the  dyer  is  often  called  upon  to  ob- 
tain or  avoid.  The  spirit-tub  in  which  the  yarn  is  wrought 
should  stand  from  2°  to  2|°  Twaddell. 

Barwood  Spirits. — These  are  named  from  being  used  as  the 
mordant  for  dyeing  with  that  wood.    They  are  prepared  with 

1  lb.  Nitric  acid, 

6  lbs.  Hydrochloric  acid, 

adding  gradually,  as  dissolved,  If  ounce  of  tin  to  the  pound  of 
the  mixture;  or — 

1  Nitric  acid, 

4  Hydrochloric  acid, 

2  ozs.  of  tin  per  lb. 

This  spirit  should  not  be  used  within  at  least  twelve  hours  after 
15 


226 


MORDANTS. 


its  preparation.  There  are  also  other  variations  in  the  prepa- 
ration of  this  spirit;  they  vary  generally  from  4  to  7  hydro- 
chloric acid.  Excess  of  tin  in  this  mordant  is  avoided.  The 
same  principle  regulates  the  tint  more  or  less.  Nitric  acid 
gives  the  red  a  brown  or  crimson  hue.  The  working  solution 
is  2J-°  Twaddell;  but  this  dye  requires  some  experience  and 
attention  to  manage  it  well. 

Plum  Spirits,  so  called  from  being  used  with  a  decoction  of 
logwood  to  prepare  a  dye  solution  of  a  deep  wine  or  plum  color, 
sometimes  termed  a  French  tub — 

7  lbs.  Hydrochloric  acid, 
1  lb.  Nitric  acid, 

adding  by  degrees,  as  dissolved,  1J  ounce  tin  to  the  pound  of 
mixture;  or, 

1  Nitric  acid, 
5  Hydrochloric, 

1J  ounce  tin  to  the  pound  of  acid, 

Some  prepare  it  by  dissolving  the  tin  in  hydrochloric  acid  alone. 
In  that  case,  the  vessel  containing  the  acid  should  be  placed  in 
a  hot  situation;  it  is  generally,  indeed,  placed  in  another  ves- 
sel containing  boiling  water.  The  spirits  are  also  prepared  by 
dissolving  some  of  the  salts  of  tin  in  hydrochloric  acid.  For 
1J  to  2  lbs.  of  logwood  used,  1  lb.  of  the  spirits  is  added. 

Yellow  Spirits,  as  before  mentioned  (page  183),  were  pre- 
pared with  sulphuric  instead  of  nitric  acid,  but  they  are  not 
now  used. 

The  above  embraces,  with  very  little  modification,  almost  all 
the  qualities  of  spirits  used  for  cotton.  That  termed  oxymuriate 
of  tin,  used  often  for  woollens  and  silks,  is  prepared  by  adding 
to  a  solution  of  the  salts  of  tin  in  hydrochloric  acid,  some  ni- 
tric acid,  which  causes  effervescence,  and  an  escape  of  red  fumes 
of  nitrous  oxide,  in  consequence  of  the  peroxidizing  of  the  tin. 
The  same  result  is  often  observed  in  the  preparation  of  the 
spirits  named  above,  when  the  tin  is  added  too  rapidly,  and 
heat  is  developed;  there  is  then  a  rapid  solution,  and  fumes  of 
nitrous  oxide  are  given  off,  producing  what  the  dyers  call  firing. 
Fired  spirits,  or  spirits  thus  peroxidized,  give  brownish,  dull, 
and  unsatisfactory  colors. 

Several  qualities  of  spirits  are  used  forwroollens  and  also  for 
silk,  by  adding  sal  ammoniac,  or  common  salt,  to  nitric  acid, 
along  with  the  tin — the  former  most  commonly — by  this  method 
a  double  salt  of  chloride  of  tin  and  ammonia  is  produced.  The 
proportions  of  the  acid  and  the  sal  ammoniac  and  tin  are  also 
varied  for  different  objects ;  but  spirits  prepared  in  this  way 
are  seldom  if  ever  used  for  cotton. 


MORDANTS. 


227 


Nitrate  of  Iron  is  prepared  by  taking  a  quantity  of  nitric 
acid,  and  adding  clean  iron  (generally  old  hoops  with  the  rust 
beaten  off)  as  long  as  the  metal  will  dissolve.  The  acid  is  best 
to  be  diluted  in  the  proportion  of  about  one  part  to  six  of  water; 
and  after  it  has  ceased  to  act  upon  the  iron,  all  the  metal  not 
dissolved  ought  to  be  removed,  otherwise  the  nitrate  will  con- 
tinue to  dissolve  more  of  it,  and  precipitate  oxide  of  iron,  and 
thereby  produce  a  thick  insoluble  mass  at  the  bottom  (see  page 
160).  Some  prefer  to  add  only  a  small  quantity  of  iron  for 
light  shades,  but  we  have  never  seen  any  advantage  in  such  a 
mode  of  proceeding.  The  iron  and  nitric  acid  ought,  however, 
to  be  weighed,  and  have  a  fixed  relation  to  each  other.  This 
solution  of  iron  should  be  kept  in  the  dark. 

Nitric  acid,  mixed  with  much  sulphuric  or  muriatic  acid, 
does  not  answer  well  for  this  solution,  as  the  salts  of  these  acids 
being  crystallizable,  require  more  water  than  the  acids  generally 
have  to  hold  them  in  solution.  Hence  the  presence  of  these 
acids  in  quantity  may  cause  a  confused  crystalline  mass  to  be 
formed  at  the  bottom  of  the  vessel  in  which  the  iron  is  dis- 
solved. But  the  small  quantities  of  these  acids,  often  present 
in  commercial  nitric  acid,  are  not  of  material  importance. 

Acetate  of  Iron  and  Alumina. — This  mordant  is  now  sel- 
dom used;  but  it  is  useful  for  dyeing  wine  colors,  &c,  with  log- 
wood. It  is  prepared  by  dissolving  equal  parts  of  copperas 
and  alum  in  boiling  water,  then  adding  a  solution  of  acetate  of 
lead  as  long  as  a  precipitate  is  formed.  Allowing  this  to  set- 
tle, the  clear  solution  is  the  double  acetate.  But  a  better  and 
cheaper  mode  of  preparing  is  to  mix  black  iron  and  red  liquor 
together,  which  form  the  mordant  in  question. 

Acetate  of  Alumina,  or  Pyrolignite  of  Alumina  (see  page 
144  for  an  account  of  its  preparation,  and  the  mode  of  testing 
it).  It  is  not,  however,  prepared  by  the  dyer.  We  may  men- 
tion, as  this  mordant  is  often  dried  upon  the  cloth  in  stoves  at 
a  high  heat,  that  care  should  be  taken  not  to  allow  two  pieces 
of  the  cloth  to  hang  too  closely  together,  which  prevents  a  free 
circulation  of  air;  nor  ought  the  stove  to  be  too  close,  otherwise 
the  warm  vapor  of  the  acetic  acid  will  react  upon  the  mordant 
in  the  cloth,  and  give  an  unequal  dye,  full  of  dark  parts,  thus 
rendering  the  color  cloudy. 

Black  Iron  Liquor. — This  is  pyrolignite  of  iron  prepared 
by  allowing  iron  to  steep  in  pyroligneous  acid.  It  is  not  pre- 
pared by  the  dyer.  We  have  also  given  a  method  of  testing 
it  (page  158). 

Iron  and  Tin  for  Eoyal  Blue. — This  is  not  prepared  to 
stand  in  reserve,  but  only  when  about  to  be  used.  The  iron 
used  for  this  color  should  be  well  killed,  that  is,  the  acid  should 


228 


MORDANTS. 


be  well  saturated  with  iron,  and  produce  a  solution  of  a  deep 
dark  red.  Some  dyers  add.  a  little  muriatic  acid  to  the  iron 
when  it  is  to  be  used  along  with  the  tin.  The  crystals  of  tin 
should  be  added  to  the  iron  liquor  immediately  before  entering 
the  goods,  and  the  liquor  should  be  well  stirred  to  prevent  in- 
equality. 

Acetate  of  Copper. — This  is  sometimes  prepared  in  the  dye- 
house  in  the  same  manner  as  acetate  of  alumina,  viz.,  by  adding 
to  a  hot  solution  of  sulphate  of  copper  (blue-stone)  a  solution 
of  acetate  of  lead;  the  clear  liquor  is  acetate  of  copper.  It  is 
better,  however,  to  purchase  it  in  the  crystallized  state;  this 
forms  a  good  alterant  for  logwood  blues,  but  it  is  not  much 
used  in  cotton  dyeing. 

Bichromate  of  potash  has  of  late  been  introduced  as  a  mor- 
dant for  cotton  with  considerable  success,  especially  in  mixed 
fabrics  of  cotton  and  wool. 

There  are  a  variety  of  other  mordants  used  in  woollen  and 
silk  dyeing,  but. these  we  do  not  particularize  here,  but  proceed 
to  enumerate  a  few  theoretical  considerations  concerning  the 
action  of  mordants  generally,  upon  silk,  cotton,  or  wool. 

Cream  of  tartar,  or  bitartrate  of  potash,  is  a  very  feeble  mor- 
dant alone,  still  it  is  universally  employed  in  dyeing  woollen 
fabrics.  When  used  along  with  alum,  sulphate  of  iron,  or 
chloride  of  tin,  it  is  a  strong  mordant,  probably  owing  to  de- 
composition; the  sulphuric  acid  of  the  alum  and  iron,  and  the 
chlorine  with  the  tin,  may  take  the  potash  from  the  tartar,  and 
the  alumina,  iron,  or  tin,  be  converted  into  a  tartrate,  and  in 
that  state  combine  more  readily  with  the  wool,  and  be  much 
less  destructive  of  the  fabric.  Woollen  goods  seem  to  require 
certain  thermal  and  acid  conditions  of  the  mordant ;  and  it  is 
known  that  a  portion  of  the  wool  dissolves,  and  an  equivalent 
of  the  mordant  takes  its  place  ;  this  has  been  especially  demon- 
strated of  alum  mordants. 

For  silk,  the  alum  mordant  is  always  used  cold,  otherwise 
the  lustre  of  the  silk  is  destroyed;  and  alum,  having  the  least 
quantity  of  acid,  is  the  best  and  most  effective  mordant.  This 
explains  why  the  Roman  alum  is  always  preferred.  It  may 
also  be  remarked  that  silk,  in  relation  to  alum,  comes  closest  to 
cotton. 

We  copy  the  following  theory  of  the  action  of  mordants, 
by  M.  Dumas,  from  the  Pharmaceutical  Times  (vol.  ii.  p.  63): — 

"Cream  of  tartar,  or  bitartrate  of  potash,  constitutes  by 
itself  a  feeble  mordant,  but  which  is  very  often  used  in  dyeing 
light  woollen  stuffs,  to  which  we  may  wish  to  give  a  delicate 
but  brilliant  shade.  It  is  also  employed  in  the  dyeing  of  ordi- 
nary woollen  goods,  but  here  it  is  associated  with  alum,  sul- 


MORDANTS. 


I 

229 


phate  of  iron,  chloride  of  tin,  &c.  Its  influence,  under  these 
circumstances,  consists  evidently  in  determining  a  double 
decomposition,  from  which  we  have  produced  a  sulphate  of 
potash  or  chloride  of  potassium,  whilst  the  tartaric  acid  com- 
bines with  the  alumina,  the  peroxide  of  iron,  or  the  oxide  of 
tin.  Now  it  is  very  probable  that  the  coloring  matters  remove 
the  alumina,  the  peroxide  of  iron,  or  the  oxide  of  tin,  more 
readily  from  tartaric  than  from  sulphuric  acid.  Moreover, 
the  presence  of  free  sulphuric  acid  would  certainly  prove 
injurious,  as  well  to  the  stuff  as  to  the  coloring  matter,  whilst 
free  tartaric  acid  can  exercise  no  unfavorable  action  over  them. 

"The  operation  of  subjecting  wool  to  the  alum  mordant  is 
always  effected  at  the  boiling  point;  the  mixture  used  in  this 
process  is  a  compound  of  alum  and  of  cream  of  tartar.  One 
of  the  objects  of  this  addition  is  to  free  the  bath  of  the  car- 
bonate of  lime  which  the  water  generally  retains  in  solution, 
and  which,  acting  on  the  alum,  would  determine  its  partial 
decomposition  by  producing  an  insoluble  subsulphate  of  alu- 
mina and  potash,  and  this  accumulating  on  the  stuff,  and 
becoming  unequally  fixed  upon  its  surface,  would  lead  to 
stains  or  blotches  on  passing  the  material  through  the  dye- 
bath.  But,  independently  of  the  above  effect,  which  might  be 
produced  by  any  acid,  cream  of  tartar  appears  to  be  capable 
of  effecting  a  farther  object,  by  inducing  a  double  decomposi- 
tion, which  transforms  the  alum  into  a  tartrate  of  alumina. 
However  this  may  be,  after  one  or  two  hours'  boiling  in  the 
alum-bath,  the  cloth,  which  should  be  constantly  agitated  so  as 
to  cause  a  more  equal  application  of  the  mordant,  is  withdrawn 
from  the  copper,  and,  after  thoroughly  draining,  it  should  be 
put  aside  for  two  or  three  days,  when  we  wish  to  dye  it  with 
any  full-bodied  color.  Experience  has  proved  that  this  repose 
after  the  use  of  the  mordant  greatly  favors  the  union  of  the 
latter  with  the  stuff.  In  applying  the  tin  mordants,  we  also 
make  use  of  cream  of  tartar.  It  is,  moreover,  an  indispensable 
addition  where  we  desire  to  fix  the  salts  of  iron  previously  to 
dyeing  in  black. 

"Woollen  cloth,  on  being  dipped  into  a  cold  aqueous  solu- 
tion of  alum,  appropriates  to  itself  a  part  of  this  salt,  but  with- 
out undergoing  any  very  sensible  alteration.  MM.  Thenard 
and  Board  have,  indeed,  proved  that  cloth,  when  thus  treated 
by  a  cold  solution  of  alum,  gives  up  this  salt  to  boiling  water, 
and  that,  after  a  few  washings  performed  at  the  boiling  point, 
it  will  have  parted  with  the  whole  of  the  alum  which  it  had 
received  in  the  cold  bath.  When,  however,  cloth  is  boiled  in 
a  solution  of  alum,  it  yields  to  this  liquid  a  portion  of  its  organic 


230 


MORDANTS. 


matter,  which  becomes  dissolved  ;  but,  at  the  same  time;  It 
absorbs  an  equal  amount  of  the  alum. 

uWe  have  now  merely  to  show  the  action  which  wool  under- 
goes when  brought  into  contact  with  alum  and  cream  of  tartar 
at  one  and  the  same  time.  It  is  very  possible  that  there  may 
be  in  this  case  a  simultaneous  fixation  of  alum,  as  well  as  of 
the  double  tartrate  of  alumina  and  potash,  and  of  tartaric  acid. 
The  presence  of  alum  in  the  cloth  when  taken  from  the  boiling 
solution  is  very  evident;  that  of  the  tartrate  of  alumina  and 
potash  and  of  free  tartaric  acid  is  only  presumable. 

"Silk,  in  like  manner,  unites  itself  with  alum  when  placed 
in  a  cold  solution  of  this  salt,  and  afterwards  parts  with  it  to 
boiling  water ;  it  may  be  reproduced  from  this  liquor  by  evapo- 
ration. The  action  of  silk  on  acetate  of  alumina  is  identical 
with  that  of  wool.  It  at  first  absorbs  this  salt  in  its  pure  form ; 
then  by  desiccation  it  loses  some  acetic  acid,  and  retains  a 
mixture  of  the  acetate  together  with  alumina  in  its  free  state ; 
it  gives  up  a  farther  portion  of  this  acetate  to  boiling  water. 

"The  alum  mordant  is  always  used  cold  with  silk;  if  em- 
ployed hot,  it  would  destroy  its  lustre.  The  bath  should  not 
contain  cream  of  tartar  when  it  is  intended  for  this  material; 
on  the  contrary  we  here  have  recourse  to  a  variety  of  alum  of 
as  neutral  a  character  as  possible. 

"The  theory  of  the  action  of  mordants  is  connected  in  the 
closest  manner  with  that  of  dyeing.  It  may,  in  fact,  be  viewed 
under  two  very  different  aspects.  Sometimes  we  admit  that 
there  exists  a  true  combination  between  the  stuff  and  the  color- 
ing matter — a  combination  which  can  only  be  determined  by  a 
veritable  affinity  between  these  two  bodies,  and  which  will 
present  a  condition  analogous  to  that  which  occurs  in  all  chemi- 
cal combinations  ;  that  is  to  say,  a  state  of  saturation,  beyond 
which  the  union  of  these  bodies  becomes  of  a  very  unstable 
character ;  at  other  times,  on  the  contrary,  we  regard  the  dye- 
ing of  stuffs  as  produced  by  a  nearly  mechanical  phenomenon, 
by  virtue  of  which  the  coloring  matters  become  imprisoned  in 
the  meshes  of  the  organic  filaments  contained  in  the  material 
to  be  dyed.  This  latter  opinion  is  evidently  the  better  founded. 
It  approximates  the  theory  of  dyeing  to  some  analogous 
phenomena  which  we  find  manifested  by  animal  charcoal  on 
colored  solutions ;  for,  as  the  animal  charcoal  seizes  upon  the 
coloring  matters  contained  in  an  aqueous  solution,  and  renders 
them  insoluble  by  fixing  them  in  a  purely  mechanical  manner 
within  its  own  pores ;  so  may  the  wool,  the  silk,  and  the  cotton, 
appropriate  the  coloring  matters  held  in  solution,  and,  by  fix- 
ing them  in  their  pores,  render  them  more  or  less  insoluble  to 
water.    Experience,  however,  shows  that  dyeing  thus  produced 


MORDANTS. 


231 


is  wanting  both  in  intensity  and  in  fixity — two  qualities  which 
it  derives  by  the  previous  application  of  a  mordant.  Now,  we 
can  readily  see  that  the  mordants  themselves  may  become  fixed 
in  the  tissues  by  similar  causes  to  those  which  determine  the 
fixation  of  the  coloring  matters  by  animal  charcoal.  We  know, 
in  fact,  that  this  latter  body  possesses  the  property  of  removing 
from  water  not  only  the  coloring  matters,  but  also  certain  salts. 
There  will,  therefore,  be  no  difficulty  in  imagining  that  silk, 
wool,  and  cotton  may,  in  their  character  of  porous  bodies,  purely 
and  simply  seize  upon  the  alum,  and  that  this  salt,  when  once 
imprisoned  in  the  meshes  of  the  tissue,  may,  subsequently, 
react*  upon  the  coloring  matter  according  as  this  latter,  in  its 
turn,  penetrates  the  interior  of  these  materials. 

"  We  may  then  refer  the  phenomena  of  absorption,  which 
characterize  the  fixation  of  the  mordants  and  the  penetration 
of  the  coloring  principles  into  the  tissues,  to  the  same  cause 
as  that  which  determines  the  action  of  animal  charcoal  on 
certain  soluble  salts  and  coloring  matters.  But,  if  one  of  these 
stuffs  be  impregnated  with  alum  and  then  dipped  into  a  bath  of 
soluble  coloring  matter,  it  acquires  a  very  deep  tint,  which 
appears  to  be  essentially  produced  by  a  kind  of  lac,  formed  by 
means  of  the  coloring  matter  and  the  base  of  the  mordant. 
On  the  other  hand,  in  a  great  number  of  cases,  the  mixture  of 
the  above  mordant  with  the  dye-bath  fails  in  producing  an 
insoluble  precipitate.  Thus,  when  we  mix  together  alum  and 
a  decoction  of  Brazil-wood,  no  precipitate  is  formed;  and,  to 
obtain  a  lac  from  this  liquor,  we  are  obliged  to  add  some  alkali 
or  alkaline  carbonate,  such  as  ammonia;  in  a  word,  we  must 
render  the  alumina  free.  While  admitting,  then,  in  accord- 
ance with  the  experiments  of  MM.  Thenard  and  Board,  that 
the  stuffs  fix  the  alum  in  its  natural  state,  we  must  acknow- 
ledge, at  the  same  time,  that,  by  some  special  action,  the 
tissue  subsequently  determines  the  union  of  the  base  of  the 
mordant  with  the  coloring  matter.  This  special  action  is  equi- 
valent to  that  of  the  alkali. 

"Now,  it  is  certain  that  the  above-mentioned  stuffs  possess, 
in  a  high  degree,  the  faculty  of  seizing  upon  the  insoluble 
coloring  matters  when  these  are  presented  to  them  in  their 
nascent  state.  It  is  thus  that  cotton  becomes  dyed  of  a  rose 
color  in  a  liquor  which  contains  carthamic  acid  in  suspension, 
arising  from  the  decomposition  of  carthamate  of  soda  by  an 
acid.  In  like  manner  we  find  wool  acquire  a  black  color, 
when  placed  in  a  boiling  solution  of  a  salt  of  iron  and  tannin, 
by  attracting  to  itself  the  black  precipitate  resulting  from  their 
admixture.  Consequently,  although  the  dyer  generally  endea- 
vors to  produce  the  insoluble  compound,  on  which  the  color- 

* 


232 


MORDANTS. 


ing  of  the  stuff  depends,  within  the  very  pores  of  the  tissue, 
still  we  may  affirm  that,  in  many  cases,  the  cloth  or  other 
material,  when  placed  in  presence  of  the  nascent  precipitate, 
has  the  property  of  seizing  upon  it,  and  thus  acquiring  a  shade 
of  greater  or  less  intensity. 

"It  is  to  this  property  (which  is  due  to  some  hitherto  unde- 
termined cause)  that  we  must  undoubtedly  refer  the  reaction 
which  takes  place  between  the  alum  and  the  soluble  coloring 
matters,  as  well  as  some  of  those  more  mysterious  phenomena 
which  are  manifested  in  dyeing.  How  else,  indeed,  are  we  to 
account  for  the  fact  that  wool  so  readily  takes  a  scarlet  color, 
while  cotton  and  silk  are  unable  to  fix  it?  How  explain  the 
cause  of  wool  so  easily  appropriating  the  black  precipitate 
formed  by  tannin  and  the  salts  of  iron,  while  silk,  under  the 
same  circumstances,  acquires  a  black  color  only  by  great 
trouble  and  expense  ?  How,  in  one  word,  can  we  understand 
why  certain  colors  should  fix  themselves  better  on  certain 
materials  than  on  others,  unless  it  be  by  virtue  of  some 
special  action,  wrongly  designated  by  the  name  of  affinity,  but 
which  does  not  the  less  constitute  a  force,  or  rather  a  conse- 
quence of  diverse  forces  of  which  we  must  take  full  account 
during  the  operations  of  dyeing?  To  confound,  in  fact,  a 
chemical  affinity  properly  so  called,  such  as  is  evidenced  in 
ordinary  chemical  combinations  when  produced  in  definite  pro- 
portions, with  the  phenomena  of  dyeing,  is  certainly  to  mix 
together  two  very  distinct  ideas.  The  union  of  silk  with 
Prussian  blue,  or  of  wool  with  indigo,  is  quite  a  different  thing 
.to  the  combination  of  sulphur  with  lead.  But  to  consider  the 
tissue  as  a  simple  filter,  capable  of  retaining  in  its  pores  certain 
precipitates,  and  of  receiving  from  them  peculiar  colors,  is  to 
go  equally  far  in  an  opposite  direction ;  nor  would  this  sup- 
position at  all  explain  the  mode  in  which  the  colored  lac  is 
formed  in  most  of  the  operations  of  dyeing,  operations  which 
are  effected  by  an  aluminous  salt  and  a  coloring  bath,  altoge- 
ther incapable  of  producing  any  lac,  except  by  the  addition  of 
an  alkali  for  the  purpose  of  setting  the  alumina  at  liberty,  or 
of  a  stuff  which  has  the  power  of  taking  up  the  lac  as  quickly 
as  it  is  formed. 

"  Among  the  reasons  which  induce  us  to  regard  the  insoluble 
coloring  matters  and  the  stuffs  as  capable  of  uniting  together 
by  virtue  of  some  special  force,  we  must  mention  the  facts  eli- 
cited by  the  recent  experiments  of  M.  Chevreul,  who  has  found 
that  the  stuffs  and  colors,  when  once  united,  form  products 
which  are  endowed  with  properties  differing,  according  to  the 
nature  of  the  stuff,  in  the  same  given  color.    The  properties 

4 


MORDANTS. 


233 


of  the  dyeing  matter  are,  then,  greatly  modified  by  the  pecu- 
liar action  of  the  tissue  on  the  dye.  Numerous  examples  place 
the  truth  of  this  assertion  beyond  all  question.  It  becomes, 
therefore,  perfectly  clear  that  it  is  only  by  an  attentive  and  sys- 
tematic study  of  the  specific  properties  of  the  stuffs,  in  their 
relation  to  the  various  dyeing  matters  which  we  may  desire  to 
fix  upon  them,  that  we  can  hope  to  direct  the  future  progress 
of  the  art  of  dyeing." 


234 


VEGETABLE  MATTERS 

USED  IN  DYEING. 


INTRODUCTORY  REMARKS. 

In  entering  upon  this  division  of  our  subject,  we  may  men- 
tion that  it  is  not  our  intention  to  go  through  a  systematic 
course  of  vegetable  chemistry,  but  to  confine  ourselves  to  those 
vegetable  substances  which  are  used  in  dyeing,  giving  their 
composition  and  reactions  with  bases  and  other  matters  used  in 
the  dye-house.  We  may  however  give,  in  a  few  introductory 
remarks,  a  general  outline  of  the  nature  of  vegetable  bodies. 
Let  us  then  begin  with  the  consideration  of  the  chemical 
changes  which  are  supposed  to  take  place  in  nature,  under  the 
influence  of  light,  giving  rise  to  the  various  colors  presented 
to  us  in  the  vegetable  kingdom,  which  will  probably  aid  us  in 
describing  the  artificial  means  of  imitating  nature  in  these  colors, 
although  as  yet  there  is  comparatively  little  known  concerning 
the  nature  of  these  changes.  For  a  long  time  chemists  con- 
sidered iron  to  be  the  coloring  principle  of  all  animals  and  vegeta- 
bles, being  almost  universally  diffused,  and  capable  of  assuming 
a  variety  of  colors  either  as  oxides  or  solutions;  but  it  was  af- 
terwards demonstrated  that  the  iron  present  in  any  vegetable, 
even  in  those  where  it  existed  most  abundantly,  was  altogether 
inadequate  to  produce  the  splendid  colors  which  vegetables  as- 
sume. Several  other  hypotheses  were  proposed  to  account  for 
the  colors  of  vegetables ;  but  these  hypotheses,  not  being  founded 
upon  inquiry  and  proof,  died  at  their  birth.  It  is  only  within 
these  few  years  that  the  true  method  of  ascertaining  the  nature 
and  cause  of  vegetable  colors  has  been  adopted ;  that  is,  by  the 
ultimate  analysis  of  vegetable  substances  in  all  their  stages  of 
existence;  and  since  then  a  number  of  important  facts  have 
been  made  known  respecting  this  interesting  subject,  and  new 
ones  are  daily  being  added ;  and  we  hope  that  these  discoveries 
will  be  speedily  made  available  to  the  practical  man. 

The  principal  elements  of  vegetable  substances  are  oxygen, 
hydrogen,  carbon,  and  nitrogen;  the  last  exists  in  such  a  mi- 
nute quantity,  that  in  many  cases  it  is  scarcely  appreciable  ; 
but,  according  to  the  opinion  of  Liebig,  who  stands  at  the  head 


VEGETABLE  SUBSTANCES. 


235 


of  this  department  of  chemistry,  it  is  never  absent.  It  is  to 
be  remarked,  however,  that  none  of  the  coloring  matters  of  the 
dye-woods  contain  nitrogen.  There  is  also  a  variety  of  earthy 
substances  in  vegetables,  such  as  lime,  iron,  magnesia,  soda, 
potash,  &c. ;  but  the  whole  of  these  never  exist  in  the  same 
vegetable — some  of  them  seem  indispensable  to  the  existence 
of  a  plant;  but  they  differ  according  to  the  nature  of  the  plant, 
and  the  soil  on  which  it  grows.  The  three  elements,  oxygen, 
hydrogen,  and  carbon,  enter  very  abundantly  into  the  com- 
position of  vegetables,  forming  from  95  to  99  per  cent. ;  but  it 
must  not  be  supposed  from  this,  that  all  vegetables  are  alike 
in  their  chemical  properties  ;  they  may  be,  and  are  more  varied 
than  the  mineral  kingdom,  considering  the  few  elements  which 
compose  them,  and  are  beautifully  illustrative  of  the  law  of 
definite  compounds  (page  35).  The  following  table  showing 
the  composition  of  a  few  substances  which  constitute  the  great 
mass  of  all  vegetables,  will  serve  to  illustrate  this  point : — 

Carbon.        Oxygen.  Hydrogen. 

Woody  fibre  ...  15  10  10 

Gum      ....  12  11  11 

Starch    ....  12  10  10 

Sugar    ....  12  11  11 

It  will  be  observed  from  the  table  how  little  change  is 
necessary  to  produce  an  entirely  different  compound.  It  will 
also  be  observed  that  gum  and  sugar  are  the  same  in  compo- 
sition, which  at  first  sight  appears  to  contradict  the  law  of 
definite  compounds ;  but  in  analyzing  substances  such  as  are 
named  in  the  table,  they  are  reduced  to  their  elements,  and 
although  we  obtain  the  same  weight  of  elements,  we  have  no 
positive  information  how  these  elements  may  have  been  united 
together  in  the  plant.  All  those  bodies  which  differ  in  proper- 
ties, and  at  the  same  time  give  the  same  number  and  weight 
of  elements,  are  termed  isomeric,  signifying  equal  parts.  The 
discovery  of  bodies  having  the  same  number  of  elements,  and 
differing  in  their  chemical  properties,  excited  much  interest 
among  chemists,  and  has  led  to  much  careful  study  and  investi- 
gation; the  result  has  been  rather  unfavorable  to  the  doctrine 
of  isomerism  ;  there  are  substances  which  our  neighbors  on  the 
other  side  of  the  water  would  designate  the  same  with  a  differ- 
ence— the  difference  is  supposed  to  be  in  the  numerical  arrange- 
ment of  the  elements.  As,  for  example,  hydrogen  and  carbon 
will  combine  in  the  proportion  of  two  and  two,  four  and  four, 
and  eight  and  eight,  forming  three  substances,  differing  con- 
siderably in  chemical  properties,  although  the  elements  are 
combined  in  the  same  relation ;  but,  interesting  as  this  subject 


236 


VEGETABLE  SUBSTANCES. 


is,  we  cannot  in  the  mean  time  enter  into  any  lengthened 
details — it  shows  us,  however,  the  extensive  means  employed 
by  nature  for  giving  us  a  variety  of  substances.  Another  point 
to  be  observed  from  the  above  table  is,  that  the  oxygen  and 
hydrogen  in  each  of  these  compounds  are  in  the  same  propor- 
tion, or  in  that  relative  proportion  in  which  they  unite  to  form 
water.  Now,  it  may  be  stated  as  a  general  rule,  that  when 
oxygen  and  hydrogen  are  united  to  carbon,  in  the  proportion 
in  which  they  form  water,  the  resulting  compounds  are  of  a 
saccharine  or  mucilaginous  character;  and  when  vegetable 
compounds  have  hydrogen  united  to  carbon  without  oxygen, 
or  when  there  is  less  of  that  element  than  would  be  required 
to  convert  the  hydrogen  present  into  water,  the  resulting  com- 
pounds are  generally  oily,  resinous,  or  alcoholic.  A  table  of 
the  composition  of  a  few  of  these  substances  will  illustrate 
this : — 

Oxygen. 
1 

5 
5 

2 
2 
1 

When  the  proportion  of  oxygen  united  to  carbon  is  in 
greater  quantity  than  the  hydrogen,  or  when  no  hydrogen  is 
present,  the  resulting  compounds  have  generally  an  acid  cha- 
racter ;  green  fruits  are  in  this  state,  which  gives  them  their 
sour  taste,  and  makes  them  deleterious  to  health,  either  by 
giving  too  much  acid  to  the  stomach,  or  the  acid  being  of  a 
directly  poisonous  nature;  but,  as  the  fruit  ripens,  it  takes  in 
or  assimilates  more  hydrogen,  and  the  acid,  or  at  least  part  of 
the  acid,  is  converted  into  a  saccharine  compound.  The  follow- 
ing table  will  show  the  composition  of  a  few  of  the  most 
common  acids  found  in  vegetables: — 

Acetic  acid  (vinegar) 
Tartaric  acid  . 
Citric  acid  (lemon  juice) 
Gallic  acid 
Tannic  acid  . 

There  are  also  a  number  of  alkalies,  alkaloids  or  bases,  formed 
in  plants,  which  unite  with  the  acids,  constituting  a  very  im- 
portant feature  in  the.  study  of  vegetable  chemistry,  but  which 


Carbon. 

Hydrogen. 

Oil  of  turpentine  . 

.  10 

8 

Oil  of  potatoes 

.  5 

6 

Oil  of  cloves  . 

.  23 

14 

Eesin  of  gamboge  . 

.  20 

14 

Caoutchouc  . 

.  4 

4 

Beeswax 

.  37 

39 

Pyroxilic  spirit 

.  2 

4 

Alcohol . 

.  2 

3 

Carbon. 

Oxygen. 

Hydrogen 

4 

3 

3 

4 

5 

2 

4 

4 

2 

7 

5 

3 

18 

12 

8 

VEGETABLE  SUBSTANCES. 


237 


we  will  not  in  the  mean  time  enter  upon  farther  than  to  state 
that  they  almost  all  contain  nitrogen  as  an  ingredient. 

These  being  the  nature  and  composition  of  the  principal 
vegetable  compounds,  we  shall  now  inquire  into  the  cause  of 
their  assuming  certain  colors,  and  the  effects  which  acids  have 
upon  these  colors. 

In  our  remarks  upon  light  (page  25),  we  mentioned  that 
colors  depend  wholly  upon  the  reflection  and  absorption  of 
light,  by  the  apparently  colored  substance;  but  it  was  also 
mentioned,  that  this  result  depends  upon  the  chemical  consti- 
tution of  the  particular  substance;  hence,  the  inquiry  into  the 
cause  ^of  vegetable  colors  becomes  a  chemical  one;  and,  from 
the  chemical  laws  above  described,  these  colors  must  have  a 
definite  constitution;  and  when  any  change  of  color  takes  place, 
there  must  also  be  a  change  of  chemical  constitution.  In 
prosecuting  this  inquiry,  or  rather,  in  collecting  the  inquiries 
of  the  most  eminent  chemists  upon  this  subject,  we  shall  begin 
with  the  paramount  color  of  the  vegetable  kingdom,  namely, 
green. 

Green  is  well  known  to  be  a  compound  color  produced  by 
yellow  and  blue,  and  is  always  produced  upon  cloth  by  dyeing 
it,  first  the  one  color  and  then  the  other.  It  is  not  always  the 
yellow  that  is  dyed  first,  according  to  the  description  in  chemi- 
cal books;  but  sometimes  the  blue,  according  to  the  nature  of 
the  dyeing  agent,  which  will  be  explained  in  its  proper  place. 
Speaking  of  vegetable  green,  Berthollet  says:  "The  green  of 
plants  is  undoubtedly  produced  by  a  homogeneous  substance, 
in  the  same  way  as  the  greater  number  of  hues  which  exist  in 
nature.  This  color  owes,  then,  its  origin  sometimes  to  simple 
rays  and  sometimes  to  a  union  of  different  rays ;  and  some 
other  colors  are  in  the  same  predicament.  Were  the  green  of 
plants  due  to  two  substances,  one  of  which  is  yellow  and  the 
other  blue,  it  would  be  extraordinary  if  we  could  not  separate 
them,  or  at  least  change  their  proportions  by  some  solvent." 
This  idea  of  Berthollet,  that  the  green  of  plants  is  a  distinct 
substance,  existing  in  the  plant,  has  since  been  verified.  It  is 
obtained  by  bruising  green  leaves  into  a  pulp  with  water,  press- 
ing out  all  the  liquid,  and  boiling  the  dry  pulp  in  alcohol; 
when  the  alcohol  is  evaporated,  there  remains  a  deep-green 
matter,  which,  by  digesting  in  water,  is  dissolved,  and  freed 
from  a  little  brown  coloring  matter  with  which  it  was  mixed. 
This  substance  has  been  named  chlorophyllite.  The  formation 
of  the  chlorophyllite  seems  to  depend  entirely  upon  the  action 
of  the  solar  rays.  "It  is  known  that  the  function  of  the  leaves, 
and  other  green  parts  of  plants,  is  to  absorb  carbonic  acid, 
and,  with  the  aid  of  light  and  moisture,  to  appropriate  its  car- 


238 


VEGETABLE  SUBSTANCES. 


bon.  These  processes  are  continually  in  operation;  they  com- 
mence with  the  formation  of  the  leaves,  and  do  not  cease  with 
their  perfect  development."  But  when  light  is  absent,  or  during 
the  night,  the  decomposition  of  carbonic  acid  does  not  proceed  ; 
it  is  evident,  then,  that  a  plant  kept  always  excluded  from  the 
light,  must  have  a  difference  in  its  composition.  uNo  one 
can  have  failed  to  observe  the  difference  between  vegetables 
thriving  in  the  full  enjoyment  of  light,  and  those  which  grow  in 
obscure  situations,  or  which  are  entirely  deprived  of  its  agency  ; 
the  former  are  of  brilliant  tints — the  latter  dingy  and  white. 
Numerous  familiar  instances  might  be  cited,  especially  among 
our  esculent  vegetables;  the  shoots  of  a  potato  produced  in  a 
dark  cellar  are  white,  straggling,  and  differently  formed  from 
those  which  the  plant  exhibits  under  its  usual  circumstances 
of  growth.  Celery  is  cultivated  for  the  table  by  carefully  ex- 
cluding the  influence  of  light  upon  its  stem ;  this  is  effected  by 
heaping  the  soil  upon  it,  so  as  entirely  to  screen  it  from  the 
solar  rays ;  but  if  suffered  to  grow  in  the  ordinary  way,  it  soon 
alters  its  aspect,  throws  out  abundant  shoots  and  leaves,  and, 
instead  of  remaining  white  and  of  little  taste,  acquires  a  deep- 
green-color,  and  a  peculiarly  bitter  and  nauseous  flavor.  The 
heart  of  the  common  cabbage  is  another  illustration,  and  the 
rosy  colored  aspect  of  the  sides  of  fruit  is  referable  to  the  same 
cause.  Changes  yet  more  remarkable  have  been  discovered  in 
plants  vegetating  entirely  without  exposure  to  light.  In  visit- 
ing a  coal-pit,  Professor  Robinson  found  a  plant  with  a  large 
white  foliage,  the  form  and  appearance  of  which  were  quite  new 
to  him;  it  was  left  at  the  mouth  of  the  pit,  when  the  subter- 
ranean leaves  died  away,  and  common  tansy  sprung  from  the 
roots."* 

Some  very  curious  and  interesting  results  have  been  obtained 
by  Mr.  Hunt  and  others,  respecting  the  effects  of  the  different 
rays  of  light  upon  vegetable  substances,  all  going  to  prove  the 
great  influence  exerted  by  that  agent  over  the  vegetable  king- 
dom, and  that  to  it  we  are  indebted  for  the  beauty  of  our  fields 
and  gardens. 

From  these  facts  we  see  that  the  green  color  of  vegetables  is 
owing  to  a  peculiar  approximate  element  existing  in  the  vege- 
table, not  invariably,  nor  altogether  essential  to  the  plant,  but 
depending  upon  circumstances;  these  circumstances  being  at 
the  same  time  the  best  for  the  health  and  existence  of  the  plant. 
This  color  differs  from  the  other  colors  of  vegetables  in  the 
time  of  its  appearing.  Flowers  of  plants  do  not  appear  till  the 
plant  has  reached  a  certain  state  of  maturity ;  but  whenever  a 


*  Braude's  Manual  of  Chemistry. 


VEGETABLE  SUBSTANCES. 


239 


plant  rises  above  the  soil,  it  immediately  begins  to  assume  the 
green  hue,  and  this  hue  is  continued  till  the  object  of  the  leaves 
is  completed.  When  a  chemical  change  takes  place,  the  green 
passes  away,  and  another  color,  reddish-yellow,  takes  its  place. 
These  changes  are  effected  in  different  degrees,  and  in  different 
lengths  of  time,  just  according  as  the  leaves  have  the  property 
of  absorbing  oxygen  gas.  Those  leaves  which  continue  longest 
green  absorb  oxygen  slowest.  The  leaves  of  the  holly  will 
only  absorb  a  small  fraction  of  oxygen,  in  the  same  time  that 
the  leaves  of  the  poplar  and  beech  will  absorb  eight  or  nine 
times  their  bulk.  These  last  are  remarkable  for  the  rapidity 
and  e&se  with  which  the  color  of  their  leaves  changes.  That 
leaves  do  absorb  oxygen  gas  when  they  change  color  in  autumn, 
and  that  it  is  owing  to  the  absorption  of  this  gas,  may  be  veri- 
fied by  placing  some  green  leaves  of  the  poplar,  the  beech  and 
the  holly  under  the  receiver  of  an  air-pump,  drying  them 
thoroughly,  and  keeping  them  excluded  from  light;  when  taken 
out,  wet  them  with  water,  and  place  them  immediately  under  a 
glass  globe  full  of  oxygen  gas,  when  they  will  change  color; 
and  it  will  be  found  that  the  change  of  color  is  just  in  propor- 
tion to  the  quantity  of  oxygen  each  absorbs.  The  consequence 
of  this  absorption  is  the  formation  of  an  acid;  in  accordance 
with  the  law  mentioned  before.  This  acid  changes  the  chloro- 
phyllite,  or  green  principle,  from  green  to  yellow,  and  then  to 
a  reddish  hue.  If  we  treat  green  leaves  with  an  acid,  the  same 
changes  of  color  take  place,  and  if  we  macerate  a  red  leaf  in 
potash  it  becomes  green. 

The  green  of  leaves,  and  the  colors  of  flowers,  are  common 
to  all  vegetables  under  the  influence  of  light;  but  there  are  a 
number  of  coloring  substances  in  vegetables  which  are  pecu- 
liar to  certain  orders,  and  which  exist  as  proximate  elements 
sometimes  in  the  leaves,  in  the  woody  part,  in  the  juice,  in  the 
bark,  in  the  flower,  in  the  seeds,  and  in  the  roots.  Several  of 
these  have  been  made  subservient  to  our  use  in  the  art  of  dye- 
ing, and  will  be  noticed  separately. 

The  various  and  beautiful  colors  of  flowers  are  produced  by 
a  somewhat  different  process  from  that  of  the  green  of  the 
leaves,  in  so  far  as  they  do  not  appear  until  the  plant  has  at- 
tained a  certain  state  of  maturity.  "The  leaves  of  the  plant 
being  fully  developed,  they  take  in  more  nourishment  from  the 
atmosphere  than  what  is  necessary  for  the  existence  of  the  plant. 
This  extra  nourishment  takes  a  new  direction  ;  a  peculiar  trans- 
formation takes  place;  new  compounds  are  formed,  which  fur- 
nish constituents  of  the  blossoms;  fruit,  and  seed."* 

*  Liebig's  Agricultural  Chemistry. 


210 


VEGETABLE  SUBSTANCES. 


Many  attempts  have  been  made  to  transfer  the  coloring 
matter  of  flowers  to  cloth,  but  without  success.  In  general, 
they  are  so  fugitive  as  to  change  the  moment  they  are  brought 
into  contact  with  the  atmosphere,  and  such  of  them  as  can  be 
extracted  have  no  affinity  for  the  cloth.  If  a  third  substance 
be  used  to  give  this  affinity,  it  destroys  the  original  color  of 
the  vegetable. 

It  is  very  probable  that  all  the  colors  of  flowers  depend  upon 
only  a  few  proximate  elements  formed  in  the  vegetable,  in  the 
manner  already  described,  and  that  their  various  hues  are  the 
consequence  of  the  presence  of  acids  affecting  more  or  less  this 
coloring  substance.  This  is  the  most  probable  hypothesis  that 
has  been  framed,  and  with  which  we  must  rest  satisfied  till 
more  accurate  experiments  verify  its  truth,  or  give  us  a  better. 
The  following  summary  of  experiments  will  give  some  idea  of 
the  views  held  upon  this  subject:  "The  expressed  juice  of 
most  red  flowers  is  blue;  hence  it  is  probable  that  the  coloring 
matter  in  the  flower  is  reddened  by  an  acid,  which  makes  its 
escape  when  the  juice  is  exposed  to  the  air.  The  violet  is  well 
known  to  be  colored  by  a  blue  matter,  which  acids  change  to 
red;  and  alkalies  and  their  carbonates  first  to  green  and  then 
to  yellow.  The  coloring  matter  of  the  violet  exists  in  the  petals 
of  red  clover,  the  red  tips  of  the  common  daisy  of  the  field,  of 
the  blue  hyacinth,  the  hollyhock,  lavender,  in  the  inner  leaves 
of  the  artichoke,  and  numerous  other  flowers.  The  same  sub- 
stance made  red  by  an  acid,  colors  the  skin  of  several  plums; 
probably,  also,  gives  the  red  color  to  the  petals  of  the  scarlet 
geranium,  and  of  the  pomegranate-tree.  The  leaves  of  the  red 
cabbage,  and  the  rind  of  the  long  radish,  are  also  colored  by 
this  principle.  It  is  remarkable  that  these,  on  being  merely 
bruised,  become  blue,  and  give  a  blue  infusion  with  water.  It 
is  probable  that  the  reddening  acid  in  these  cases  is  the  car- 
bonic, which,  on  the  rupture  of  the  vessel  which  incloses  it 
(being  a  gas),  escapes  into  the  atmosphere.  If  the  petals  of  the 
red  rose  be  triturated  with  a  little  water  and  chalk,  a  blue  liquid 
is  obtained.  Alkalies  render  this  blue  liquid  green,  and  acids 
restore  its  red  color."* 

We  need  hardly  mention  that  the  influence  of  light  in  pro- 
ducing colors,  and  changing  them  when  produced,  is  regulated 
to  a  great  extent  by  the  vitality  of  the  plant ;  so  that  the  effects 
vary  in  intensity  according  to  the  season  of  the  year.  When 
leaves  or  flowers  are  taken  from  a  plant,  they  are  both  very 
soon  affected  by  light ;  but  it  has  been  observed  by  Sir  John 
Herschel,  that  flowers  plucked  at  an  early  period,  as  when 

*  Thomson's  Vegetable  Chemistry. 


GALLS. 


241 


newly  formed,  are  much  more  sensitive  to  light  than  at  a  later 
period  of  flowering,  showing  that  flowers  have  a  period  of 
maturity;  and  if  pulled  at  maturity,  the  coloring  compound  is 
much  more  stable,  and  resists  the  action  of  light  much  more 
powerfully  than  when  pulled  before.  This  law  of  development 
and  maturity  is  universal,  and  may  be  the  cause  of  many  of  the 
varieties — the  superiority  or  inferiority  of  many  vegetable  dyes 
even  of  the  same  kind. 

The  vegetable  substances  used  in  dyeing  may  be  divided  into 
two  classes:  first,  those  which  are  used  not  on  account  of  their 
possessing  coloring  properties,  but  because  they  possess  matters 
that  have  a  strong  attraction  for  the  fibre,  which  they  fill,  and 
also  form  insoluble  compounds  with  the  bases,  and  so  enabling 
them  to  act  the  part  of  mordants  to  the  substances  which  are 
afterwards  to  be  applied  ;  and,  second,  those  substances  that 
are  applied  or  used  for  the  coloring  matter  they  contain. 

The  substances  comprised  in  the  first  class  of  these  are 
termed  astringent,  from  their  producing  a  roughening  or  cor- 
rugating effect  upon  the  mouth,  when  tasted.  All  the  vege- 
tables that  produce  these  effects  are  found  to  contain  certain 
acids,  to  which  this  property  of  astringency  is  referable  ;  and 
the  presence  of  these  acids  gives  them  their  value  in  the  dye- 
house.    These  acids  are  gallic  acid  and  tannic  acid,  or  tannin. 

It  has  been  found,  from  the  extensive  researches  of  Dr.  Sten- 
house  on  the  vegetables  containing  these  acids,  that  the  tannin 
exists  in  them  in  a  great  variety  of  modified  forms,  or  rather 
that  they  give  certain  modified  reactions  with  chemical  agents, 
the  cause  of  which,  analysis  has  not  yet  been  able  to  define. 
For  our  purpose,  we  will  divide  these  substances  thus  acted 
upon  into  two: — 

1.  Those  which  give  a  black  precipitate  with  the  salts  of  iron 
— for  a  proper  type  of  which  may  be  cited  galls  and  sumach ; 
and, 

2.  Those  which  give  a  dark-olive  precipitate  with  iron — 
the  type  of  which  is  catechu.  The  latter  is  much  more  stable 
in  its  composition,  and  less  liable  to  change  by  standing. 

Galls. 

Upon  certain  species  of  oak  there  grow  excrescences  which 
originate  in  punctures,  made  by  a  peculiar  insect,  for  the  pur- 
pose of  depositing  her  eggs.  A  kind  of  juice  exudes  from  this 
puncture,  and  gradually  forms  round  these  ova  hard  round 
bodies,  varying  in  size  from  one-fourth  of  an  inch  to  an  inch 
in  diameter.  These  substances,  from  their  resemblance  to  nuts, 
16 


242 


GALLS. 


and  from  their  bitter  taste,  are  called  gall-nuts*  By  the 
repeated  experiments  of  many  excellent  chemists  upon  this 
substance,  it  is  considered  to  contain  two  peculiar  principles. 
One  of  these,  a  crystallizable  substance,  is  obtained  from  a 
macerated  solution  of  galls,  after  standing  in  the  air  for  a  long 
time.  This,  from  its  possessing  many  acid  properties,  is  termed 
gallic  acid.  The  other  is  that  substance  which  combines  with 
skins  during  the  process  of  tanning,  changing  them  into 
leather,  and  is  termed  tannin,  or,  from  its  having  some  acid 
properties,  tannic  acid. 

The  best  galls,  according  to  Sir  H.  Davy,  contain  26  per  cent, 
tannin  and  6.2  of  gallic  acid,  but  from  the  circumstance  of 
these  two  compounds  being  generally  found  together  in  the 
same  vegetable  and  in  variable  proportions,  it  was  thought 
probable  that  the  one  produced  the  other.  This  supposition 
was  verified  to  a  great  extent  by  M.  Pelouze, 
Fig.  13.       particularly  as  respects  the  tannin  of  galls. 

The  method  for  abstracting  tannin  from  galls 
is  as  follows:  To  a  vessel,  such  as  that  repre- 
sented in  the  annexed  figure,  is  fitted  by  means 
of  a  cork,  g,  a  funnel-shaped  tube,  and  the  neck  c 
is  kept  corked,  air-tight,  during  the  process.  At 
the  bottom  of  the  tube  is  placed  a  little  clean 
cotton,  as  shown  at  /.  Above  the  cotton  is  placed 
a  quantity  of  nut-galls  in  fine  powder,  as  shown 
at  e.  Over  this  is  poured  a  quantity  of  common 
sulphuric  ether,  sufficient  to  fill  the  rest  of  the 
tube,  as  seen  at  d.  A  cork  is  then  fitted  tightly 
to  the  opening  at  the  top  of  the  tube,  and  the 
whole  set  aside.  Next  day,  two  layers  of  liquor 
are  found  in  the  vessel  a,  one  very  light  and 
limpid,  occupying  the  upper  part,  the  other 
having  a  light  amber  color,  and  the  consistence 
of  a  syrup,  occupying  the  lower  part.  These  liquids  are  poured 
into  a  dropping  tube,  upon  which  the  finger  is  kept,  and  after 
remaining  at  rest  for  a  few  minutes,  they  again  separate;  the 
heavy  liquid  is  then  allowed  to  fall  out  into  a  capsule,  and 
the  light  liquid  retained  so  that  it  may  be  distilled  for  the  sake 
of  recovering  the  ether.  The  dense  liquid  which  is  in  the. 
capsule  is  next  to  be  washed  two  or  three  times  with  sulphuric 
ether,  and  afterwards  dried  by  a  very  gentle  heat ;  the  matter 
left  has  a  spongy  appearance,  is  very  brilliant,  and  generally 

*  The  excrescences  are  produced  by  the  cynips  (gall-wasp)  upon  the  tender 
shoots  of  the  quercus  infectoria,  a  species  of  qak  which  is  common  in  Asia 
Minor.  When  the  maggot  is  hatched,  it  eats  its  way  out  of  the  nidus.  The 
best  galls  are  those  brought  from  Aleppo  and  Smyrna. 


GALLS. 


243 


of  a  yellow  tint.  This  is  tannin  in  a  state  of  purity.  By  this 
process,  from  35  to  40  per  cent,  can  be  extracted  from  nutgalls. 

M.  Pelouze  found  that  if  a  solution  of  tannin  be  kept  closely 
corked  from  the  atmosphere,  no  change  takes  place;  but  if  left 
in  contact  with  oxygen,  the  tannin  undergoes  a  change,  and 
gallic  acid  is  formed.  Hence  he  concludes  that  gallic  acid  does 
not  exist  except  in  very  minute  quantity  in  vegetables,  and 
that  the  error  of  supposing  that  these  two  acids  existed  toge- 
ther in  vegetables,  arose  from  the  method  adopted  to  procure 
gallic  acid,  which  was  by  allowing  the  macerated  vegetable 
matter  to  stand  in  contact  with  the  air,  till  the  gallic  acid  crys- 
tallized from  the  solution,  this  being  nothing  more  than  a  pro- 
cess for  converting  tannin  into  gallic  acid  by  the  absorption  of 
oxygen. 

This  discovery  is  of  great  importance  to  the  dyer,  as  it 
points  out  the  evil  of  allowing  liquids,  which  contain  tannin, 
to  stand  exposed  to  the  air  for  any  length  of  time;  for  although 
gallic  acid  and  tannin  act  in  a  somewhat  similar  manner  with 
metallic  oxides,  yet  the  gallates  are  much  more  fugitive  than 
the  tannates.  For  example,  if  we  precipitate  tannic  acid  and 
gallic  acid  by  a  persulphate  of  iron,  they  are  both  dark  blue, 
bordering  on  black;  excepting  a  slight  change  of  shade,  the 
tannate  remains  permanent ;  but  if  the  gallate  be  allowed  to 
stand  a  few  hours,  it  is  dissolved  in  the  supernatant  liquid, 
and  becomes  almost  colorless;  the  sulphuric  acid  resumes  its 
attraction  for  the  iron,  and  crystallizes  as  a  protosulphate  (cop- 
peras), and  the  gallic  acid  is  partly  decomposed  and  partly 
crystallized.  These  changes  take  place  in  a  few  minutes,  if 
the  liquor  containing  the  precipitate  be  boiled.  Now,  if  galls, 
or,  what  is  more  commonly  used  instead,  sumach,  be  allowed 
to  stand  until  after  fermentation  takes  place,  which  is  very 
soon,  a  great  portion  of  the  tannin  is  converted  into  gallic 
acid;  and,  although  the  cloth  dyed  in  sumach  that  is  thus 
altered  should  be,  as  some  dyers  affirm,  equally  dark,  it  will 
not  be  equally  fast;  but  from  personal  experience,  we  can  say 
that  it  is  neither  equally  dark  nor  equally  beautiful.  It  can- 
not  be  so  dark,  for  gallic  acid  being  much  more  insoluble  than 
tannin,  falls  to  the  bottom  whenever  it  is  formed,  and  conse- 
quently leaves  the  supernatant  liquid  much  weaker  in  its  dye- 
ing properties. 

More  recent  discoveries  have  shown  that  tannin  is  converti- 
ble into  gallic  acid  by  other  and  much  more  rapid  means  than 
being  left  to  absorb  oxygen  :  these  are  by  the  common  processes 
of  inducing  fermentation.  It  is  well  known  that  fermentation 
is  simply  a  derangement  of  the  elements  of  certain  complex 
compounds,  and  the  rearrangement  of  these  elements  in  differ- 


244 


GALLS. 


ent  positions  and  proportions,  giving  rise  to  new  and  altogether 
different  compounds  of  a  more  simple  nature,  that  is,  having  a 
smaller  number  of  elements.  The  primary  compounds  are 
formed  under  the  unknown  influence  of  the  vital  principle  ; 
but  whenever  this  is  withdrawn,  they  seem  but  passively  to 
retain  their  chemical  conditions.  The  attraction  of  their  ele- 
ments seems  too  weak  to  enable  them  to  resist  any  marked 
change  of  circumstances.  Even  a  slight  elevation  of  tempera- 
ture is  sufficient  to  overpower  their  affinities  and  induce  change. 
As  in  the  case  of  fermentation,  if  they  are  brought  into  con- 
tact with  a  body  which  is  in  the  act  of  derangement,  that  body 
excites  the  same  derangement  in  them,  and,  the  equilibrium 
being  disturbed,  the  elements  are  left  to  arrange  themselves 
according  to  their  different  attractions.  If,  for  example,  we 
dissolve  a  little  sugar  of  grapes,  which  is  composed  of  12  car- 
bon, 12  hydrogen,  and  12  oxygen,  in  a  little  water,  and  raise 
the  solution  to  a  temperature  of  about  80°  Fah. ;  and  if  to  this 
we  add  a  little  yeast,  which  is  a  substance  whose  atoms  are  in 
the  act  of  transposition,  the  yeast  does  not  combine  chemically 
with  the  sugar,  but  it  communicates  to  it  by  contact  the  action 
of  transposition,  and  thereby  deranges  the  arrangement  which 
the  atoms  had  assumed  to  form  sugar ;  and  the  atomic  elements 
being  thus  set  at  liberty,  begin  to  arrange  themselves  differ- 
ently ;  every  three  atoms  of  the  hydrogen  combine  with  two 
of  the  carbon  and  one  of  the  oxygen,  forming  four  atoms  of 
alcohol.  The  remaining  eight  atoms  of  oxygen  unite  with  the 
remaining  four  of  carbon  in  the  relation  of  one  to  two,  forming 
four  atoms  of  carbonic  acid  gas.  Thus  the  whole  sugar  is 
converted  into  two  different  substances,  of  which  the  yeast 
forms  no  part.  It  only  acts  the  part  of  a  bold  revolutionizer, 
breaking  up  existing  combinations,  that  new  ones  may  be 
formed  from  their  elements.  Now  tannin  is  found  to  undergo 
the  same  sort  of  change  as  the  sugar,  when  brought  into  con- 
tact with  certain  substances;  and  one  of  the  new  compounds 
formed  from  this  transposition  is  gallic  acid.  M.  Antoine  has 
indeed  directly  shown  that  a  very  small  quantity  of  nutgalls 
is  capable  of  converting  a  large  quantity  of  tannin  into  gallic 
acid,  and  that  galls  contain  a  substance  capable  of  producing 
fermentation  amongst  the  elements  of  the  tannin.  The  com- 
position of  tannin,  as  compared  with  that  of  gallic  acid,  is  as 
follows : — 


TANNIN. 


GALLIC  ACID. 

7  Carbon. 
5  Oxygen. 
3  Hydrogen. 


18  Carbon. 
12  Oxygen. 
8  Hydrogen 


GALLS. 


245 


The  action  which  is  considered  to  take  place  during  the  fer- 
mentation of  tannin  by  exposure  to  the  air  is,  that  it  absorbs 
or  combines  with  eight  proportions  of  oxygen  from  the  atmos- 
phere : — 


One  proportion  of 
tannin 


Oxygen  imbibed 


18  C  ==  equal  to  j1* 
12  0  =  equal  to  f1® 
8  H  =  equal  to  |  ^ 
8  |  8 


2  proportions 
gallic  acid. 

Water. 


Carbonic 
acid. 


Now,  in  proportion  as  gallic  acid  is  inferior  to  tannin  in  its 
dyeing  properties,  will  be  the  extent  of  the  evil  of  allowing 
liquors  which  contain  tannin,  and  which  depend  upon  it  for 
their  dyeing  properties,  to  stand  till  fermentation  begins.  In 
some  liquors  this  commences  in  the  course  of  three  or  four 
days ;  much,  however,  depends  upon  the  temperature. 

But  although  galls  thus  contain  within  them  the  property  of 
a  ferment,  it  may  justly  be  asked  whether  sumach,  which  has 
in  many  operations  of  the  dye-house  superseded  the  use  of 
galls,  possesses  the  same  property  ?  The  affirmative — that  it 
does  possess  the  property  of  exciting  fermentation  in  other  sub- 
stances— has  not  yet  been  determined;  but  from  a  number  of 
experiments  upon  the  action  of  various  substances  on  tannin, 
it  would  seem  either  to  induce  or  facilitate  fermentation ;  and 
further,  we  venture  to  say,  that  the  tannin  in  sumach  is  more 
readily  converted  into  gallic  acid  than  the  tannin  of  gall  nuts. 
If  the  liquor  of  galls  be  allowed  to  stand  exposed  to  the  air,  it 
requires  a  considerable  time  before  its  tannin  is  converted  into 
gallic  acid,  but  there  are  a  number  of  substances  which,  if  put 
into  it,  cause  the  formation  of  gallic  acid  to  proceed  much 
more  quickly.  Among  others,  the  tartaric  and  malic  acids 
possess  this  property  in  a  high  degree.  Now  sumach,  accord- 
ing to  some  recent  analyses,  contains  a  great  quantity  of  malic 
acid,  which,  were  we  allowed  to  reason  from  analogy  in  chemi- 
cal science,  places  it  under  very  favorable  circumstances  for 
fermentation.  Indeed,  in  certain  seasons  of  the  year,  we  have 
known  it  to  ferment  in  forty-eight  hours.  Whether  this  fer- 
mentation was  induced  first  by  the  tannin  or  by  the  coloring 
matter  which  it  contains — for  sumach  contains  a  distinct  color- 
ing matter — we  cannot  certainly  in  the  meantime  determine. 
But  this  we  well  know,  that  a  very  short  exposure  to  the  air 
makes  it  lose  its  coloring  matter. 

It  was  found  by  the  author  quoted  above,  that  a  little  sul- 


246 


GALLS. 


phuric,  hydrochloric,  or  nitric  acid,  added  to  a  solution  of  galls, 
makes  it  less  liable  to  ferment  by  exposure. 

The  following  table,  abridged  from  Brande's  Manual  of 
Chemistry,  will  give  some  idea  of  the  action  of  some  metallic 
salts  upon  a  solution  of  galls  or  sumach  : — 

Names  of  Salts  used.  Color  of  Precipitates. 

Protochloride  of  manganese    .    .  Dirty  yellow. 
Protosulphate  of  iron  (copperas)  .  Purple  tint. 
Persulphate  of  iron      ....  Black. 
Chloride  of  zinc  (muriate  of  zinc)  Dirty  yellow. 
Protochloride  of  tin      ....  Straw  color. 

Perchloride  of  tin  Fawn  color. 

Sulphate  of  copper  (blue-stone)  .  Yellow-brown. 

Nitrate  of  copper  Grass-green. 

Nitrate  of  lead    .     .  .  .     .     .    .  Dingy  yellow. 

Tartrate  of  antimony  and  potash  Straw  color. 

Tartrate  of  bismuth  and  potash  .  Copious  yellow,  or  orange. 

Sulphate  of  uranium    ....  Blue-black. 

Sulphate  of  nickel  Green. 

Protonitrate  of  mercury    .     .    .  Yellow. 

In  attempting  to  draw  a  practical  inference  from  some  of 
these  results,  we  would,  for  example,  conclude  that  persulphate 
of  iron  is  much  better  adapted  for  dyeing  blacks  than  protosul- 
phate, as  the  former  is  mentioned  as  producing  a  deep  black, 
while  the  latter  gives  only  a  purple  tint.  It  is  much  to  be 
regretted  that  in  making  out  these  tables,  care  is  not  taken  to 
give  the  results  in  all  their  bearings.  What  is  mentioned  of 
these  two  salts  is  correct,  at  the  instant  the  mixtures  are  made  : 
but  in  the  course  of  twenty  minutes  the  black  from  the  persul- 
phate becomes  a  brownish  slate,  whereas  the  purple  tint  of 
the  protosulphate  changes  during  the  same  time  to  a  deep 
black  ;  and  these  changes  continue  till  the  former  has  become 
a  light-yellowish  slate,  and  the  latter  a  perfect  ink  black. 

"W  hen  trying  the  difference  of  effect  produced  by  the  per- 
sulphate and  protosulphate  of  iron  upon  pure  tannin  and  gallic 
acid,  it  may  further  be  observed,  that  the  changes  produced 
with  tannin  are  somewhat  similar  to  those  which  occur  in  a 
solution  of  galls.  With  gallic  acid  the  persulphate  gives  at 
first  a  black  precipitate,  not  so  dark  as  the  tannate,  but  in  a 
few  minutes  it  changes  to  an  olive,  and  continues  changing 
till  it  becomes  almost  colorless.  With  the  protosulphate,  at 
first  the  color  is  scarcely  visible,  but  after  an  hour's  exposure, 
it  assumes  a  rich  violet.  From  these  facts,  it  may  be  concluded 
that  tannin  is  superior  to  gallic  acid  as  a  dyeing  agent  for  black  ; 
moreover,  the  compound  formed  is  more  insoluble. 


GALLS. 


247 


Another  circumstance  which  modifies  the  results  of  these 
experiments  in  their  application  to  dyeing,  is  the  quality  of 
the  water  used.  If  the  experiments  be  performed  with  dis- 
tilled water,  it  will  be  found  on  repeating  them  with  common 
spring  water,  that  one-half  of  the  quantity  of  stuffs  will  give 
the  same  depth  of  color ;  and  that  the  colors,  in  this  instance, 
have  more  of  a  purple  hue,  and  are  much  more  permanent. 
This  may  be  illustrated  by  a  very  simple  experiment.  Take 
two  glass  jars  of  equal  size,  fill  them  half  full  with  distilled 
water,  and  add  an  equal  quantity  of  a  solution  of  galls,  or 
sumach;  put  into  each  an  equal  number  of  drops  of  a  solution 
of  protosulphate  of  iron  (copperas) ;  the  change  of  color  is 
scarcely  perceptible.  But  fill  up  one  to  the  brim  with  spring 
water,  and  it  almost  instantly  becomes  a  dark  reddish  black. 
Allow  both  jars  to  stand  for  an  hour,  the  solution  with  the 
distilled  water  will  have  become  a  deep  violet,  while  the  other, 
notwithstanding  the  double  quantity  of  water,  is  so  dark  that 
no  light  is  transmitted  ;  and  it  will  require  one-half  more  water 
to  reduce  it  to  the  same  shade  as  the  other,  but  still  retaining 
more  of  the  reddish  hue — which,  by  the  way,  makes  it  superior 
for  black.  It  will  also  be  found  to  be  much  more  insoluble, 
and  to  require  a  greater  proportion  of  acid  to  decompose  it.  If 
soft  or  filtered  river  water  be  used  instead  of  distilled  water, 
the  distinction  is  not  so  great,  but  still  the  difference  is  equal 
to  one-half.  The  best  water  which  we  have  used  for  dye- 
ing black,  and  other  saddened  colors*  gave,  by  analysis,  sul- 
phuric, muriatic,  and  carbonic  acids,  lime,  a  trace  of  silica,  and 
iron.  The  whole  solid  contents  did  not  exceed  one  grain  in  a 
fluidounce,  or  160  grains  per  gallon,  which,  we  may  remark, 
is  a  large  quantity  (see  page  51).  These  ingredients  probably 
existed  in  the  water  as  sulphate,  carbonate,  and  muriate  of  lime, 
and  carbonate  of  iron.  The  iron  was  in  very  small  proportion ; 
the  carbonic  acid  and  lime  greatest. 

Now  a  dyer,  learning  his  trade  in  a  work-shop  where  such 
water  was  used,  could  not  fail  to  become  a  successful  dyer  of  all 
saddened  colors ;  but  were  he  taken  from  this  work  to  another 
where  soft  filtered  water  was  used,  what  would  be  the  result? 
When  he  attempted  to  dye  a  black  with  the  same  quantity  of 
dyestuff  he  formerly  used,  he  would  only  produce  a  dark-slate 
color;  and  if  he  wished  to  obtain  a  slate  color,  he  would  pro- 
duce a  gray.  In  this  dilemma,  the  dyer  adds  stuff  till  he  comes 
to  the  desired  shade ;  but  fancy-dyes,  bolstered  up  with  stuffs, 
are  not  so  pretty;  besides,  the  employer,  in  consequence  of 

*  A  technical  name  for  colors  that  are  darkened  by  sulphate  of  iron,  which 
includes  drabs,  fawns,  slates,  gray,  some  kinds  of  browns,  blacks,  &c. 


248 


GALLS. 


this  extra  stuff,  must  either  submit  to  a  loss,  or  discharge  the 
dyer;  who,  no  doubt,  considering  himself  ill-used,  talks  loudly 
of  his  ability  in  dyeing  such  colors,  and  offers  to  prove  that 
the  fault  is  not  in  him,  but  the  water.  Were  this  wholly  a 
supposed  case,  we  would  pause  here,  and  make  an  apology  to 
our  brethren  for  these  remarks;  but  not  being  so,  we  will 
rather  endeavor  to  show  that  the  fault  is  the  dyer's.  Dyeing 
being  an  art  wholly  dependent  upon  chemistry  for  its  develop- 
ment and  successful  practice,  he  who  practises  it,  without  study- 
ing chemistry,  is  like  a  boy  learning  to  repeat  a  number  of 
choice  sentences  from  an  author,  without  knowing  his  letters. 
Had  the  dyer  alluded  to  known  the  principles  of  chemistry,  so 
far  as  they  are  applicable  to  his  trade,  he  would,  on  finding 
that  the  same  quantity  of  stuffs  did  not  yield  the  same  results, 
have  examined  the  water  to  discover  where  lay  the  difference, 
and  in  this  particular  case  he  would  find,  that  instead  of  add- 
ing an  extra  quantity  of  sumach,  copperas,  and  logwood,  to 
get  a  good  black,  a  little  chalk  and  hydrous  gypsum  (sulphate 
of  lime)  added  to  the  water,  would  so  qualify  it  as  to  render 
it  equally  effective  with  that  to  which  he  had  been  accustomed. 

There  are  several  kinds  of  galls,  but  the  three  following 
kinds  occur  in  commerce — Aleppo  galls,  Smyrna  galls,  and 
Bast  Indian  galls.  These  three  kinds  consist,  according  to  the 
ripeness  of  the  apples,  of  black,  green,  and  white  galls.  When 
the  galls  occur  in  commerce  mixed,  they  are  termed  "natural;" 
and  are  sorted  into  the  following  kinds:  picked  black,  natural 
black  (consisting  of  black  and  dark-green  galls),  dark-green, 
light-green,  natural  white  (light-green  and  white  galls),  and 
picked  white.  Aleppo  galls  are  the  best;  but  under  this  name 
must  be  reckoned  not  only  such  as  come  from  Aleppo,  but 
also,  those  derived  from  Mosul  in  Natalia,  and  which  are  there- 
fore called  in  Constantinople  and  Smyrna  lists,  not  Aleppo,  but 
Mosul  galls.  This  gall  recommends  itself  by  its  heaviness,  and 
the  lighter-colored  kinds  (white  and  light-green  galls)  are  fre- 
quently remarkable  from  their  large  size;  but  the  best  dis- 
tinguishing character  between  the  Mosul  and  Smyrna  galls,  is 
the  darker  kind  of  the  Mosul  galls  having  as  it  were  a  bluish 
bloom,  while  the  Smyrna  are  of  a  grayish  color.  The  Mosul 
gall,  moreover,  has  not  so  many  tubercles  as  the  Smyrna  kind. 
The  first  is  exported  from  Constantinople  and  Smyrna,  the 
latter  principally  from  Smyrna.  The  chief  markets  are  Trieste, 
Leghorn,  Marseilles,  and  London.  The  fourth  kind  of  nutgall 
is  the  marmorated  one,  which  is  brought  from  Puglia ;  the 
chief  staple  places  are  Naples  and  Trieste.  It  consists  generally 
of  large  apples,  which  have  fewer  tubercles,  and  these  not 
acute.    They  are  generally  of  a  whitish-red  and  greenish  color, 


SUMACH. 


2-19 


sometimes  also  darker.  Istria  produces  a  very  inferior  kind  of 
galls  ;  they  are  small,  commonly  of  a  reddish  color,  and  are 
much  tuberculated.  Place  of  export,  Trieste.  These  are  the 
principal  kinds,  not  to  mention  others  of  rare  occurrence  ;  for 
instance,  a  kind  of  gall  is  brought  from  Asia  Minor  and  Dal- 
matia,  which  is  hollow,  not  heavy,  and  of  a  reddish  color. 
Analysis  of  galls  by  M.  Guibourt: — 

Woody  fibre  10.5  ^|      The  luteo  gallic  acid 

Water  11.5  '  is  applied  to  the  yel- 

Tannin  65.0  j  low  coloring  matter  of 

Gallic  acid  2.0  J  the  galls. 

Ellagic  acid  and  luteo  gallic 

acid  2.0         Sometimes  white 

Extractive  matter  2.5      galls  are  dyed  by  a 

Gum  2.5      little  iron  water  being 

Starch  2.     )-  put  upon  them;  which 

Chlorophylle  0.7      darkens    them,  and 

Sugar  1.8      makes  them  appear  of 

a  better  quality. 


100.0 


Sumach. 

Called  by  botanists  rhus  coriaria,  is  a  native  of  Syria.  It  is 
diligently  cultivated  in  Spain,  Portugal,  and  in  some  parts  of 
Italy  and  Sicily,  and  known  in  the  market  as  Sicily,  Malaga, 
Trieste,  and  Verona;  the  first  is  the  best  quality.  A  quantity 
of  about  60,000  tons  of  this  dye  is  used  annually  in  this  coun- 
try. The  sumach  tree,  or  rather  shrub,  grows  to  a  height  of 
about  eight  or  ten  feet;  the  stems  are  ligneous,  and  divide  at 
the  bottom  into  many  irregular  branches ;  the  bark  is  hairy 
and  of  a  brown  color.  The  leaves  are  winged,  have  seven  or 
eight  pair  of  jagged  lobes,  and  terminate  in  an  odd  one.  The 
leaves  are  placed  alternately  upon  the  branches,  which  are  sur- 
mounted by  flowers  of  a  greenish-white  color.  The  shoots  of 
the  shrub  are  cut  down  every  year  close  to  the  roots,  and  after 
being  dried,  are  reduced  to  powder  by  means  of  a  mill ;  the 
very  fine  stems  are  often  cut  into  small  pieces,  and  put  amongst 
the  powder. 

We  have  already  referred  to  the  use  of  sumach  in  the  dye- 
house  ;  we  speak  of  it  simply  as  a  fit  substitute  for  galls,  pos- 
sessing similar  properties,  and  seemingly  passing  through  simi- 
lar decompositions  by  exposure.  A  little  sulphuric  acid  added 
to  sumach  retards  fermentation,  but  it  is  not  a  good  addition 
when  dark  shades  are  required,  and  should  only  be  used  for 


250 


SUMACH. 


sumach  which  is  to  stand  for  some  time,  or  which  is  to  be  used 
for  very  light  drabs.  In  this  case  the  color  obtained  is  more 
pleasant — technically  more  sweet;  bat  either  the  addition  of 
acid,  or  by  standing  exposed  to  the  air,  very  soon  destroys  the 
coloring  matter  which  sumach  contains,  and  also  the  depth  of 
shade  of  dye  obtained  from  it.  It  is,  therefore,  always  advisa- 
ble to  use  the  sumach  newly  boiled.  The  comparative  advan- 
tages of  using  it  newly  boiled  and  after  it  has  been  kept  for 
some  time,  can  easily  be  ascertained  by  taking  a  given  quan- 
tity, boiling  it,  and  allowing  it  to  stand  over  a  few  days ;  then 
taking  the  same  quantity,  boiling  it  the  same  length  of  time, 
heating  the  old  solution  to  the  same  temperature  as  the  new, 
and  adding  to  each  the  same  weight  of  cotton ;  the  effects  pro- 
duced will  be  very  different,  and  will,  more  than  any  written 
description,  show  the  importance  of  attending  to  this  circum- 
stance. 

Sumach  is  generally  used  when  the  metallic  base,  or  mordant, 
is  iron  or  tin,  and  is  therefore  the  bottom?  of  blacks,  reds,  &c. 
Sicilian  sumach  has  a  greenish-yellow  color.  When  bright 
colors  of  red  are  to  be  dyed  it  is  best;  also  for  barwood,  an<|| 
all  colors  that  require  clearness.  Verona  sumach  when  com- 
pared with  Sicily  has  a  fawn  tint ;  it  is  best  for  deep  reds, 
browns,  and  blacks.  When  used  for  barwood  reds  the  color 
is  heavy,  and  to  use  Sicilian  sumach  for  the  purposes  that  Vero- 
nian  is  most  suitable,  would  require  about  one  half  more  in 
quantity  for  the  same  weight  of  cloth. 

The  following  process  for  dyeing  black  will  enable  us  to 
illustrate  some  of  the  reactions  of  this  substance  in  connection 
with  the  metallic  bases  : — 

The  goods  are  allowed  to  steep  in  a  decoction  of  sumach  for 
twelve  hours ;  they  are  then  wrought  through  lime-water, 
which  gives  them  a  beautiful  bluish-green  color,  becoming  very 
dark  with  a  short  exposure  to  the  air.  If  allowed  to  stand  for 
half  an  hour,  the  green  color  passes  off,  and  the  goods  assume 
a  greenish-dun  shade.  When  they  are  at  the  darkest  shade  of 
green,  they  are  put  through  a  solution  of  copperas ;  after 
working  some  time  in  this,  and  allowing  them  to  stand  exposed 
to  the  air,  they  become  a  black.  But  if  dried  from  this,  it  is 
only  a  slate  or  dark  gray.  They  are  therefore  again  put 
through  lime-water,  which  renders  them  brown,  and  then 
wrought  through  a  decoction  of  logwood  till  the  color  of  the 
wood  has  nearly  disappeared.  A  little  copperas  is  added, 
which  throws  off  the  reddish  hue  of  the  wood,  giving  them  a 

*  Bottom  is  a  technical  term  applied  to  the  preparation  of  cotton  by  sumach 
and  the  like,  for  colors. 


SUMACH. 


251 

V'  < . 


blue  shade.  This  is  termed  raising  the  color.  The  goods  are 
washed  from  this  in  cold  water,  and  dried  in  the  shade.  When 
a  deep  blue-black  is  wanted,  the  goods  are  dyed  blue  previous 
to  steeping  in  the  sumach. 

The  passing  of  the  goods  from  the  sumach  through  lime, 
before  introducing  them  into  the  iron  solution,  is  not  essen- 
tially necessary  for  producing  the  color,  but  is  very  useful  in 
facilitating  the  operation,  and  in  giving  depth  of  hue  by  the 
iron.  This  metal  is  held  by  the  strong  affinity  of  the  acid,  but 
the  goods,  impregnated  with  lime,  being  put  into  the  copperas, 
the  lime  takes  the  acid,  and  the  iron,  liberated  immediately  and 
in  greater  quantity,  takes  to  the  tannin  of  the  sumach.  The 
passing  through  lime-water  from  the  copperas  solution,  is  for 
the  purpose,  also,  of  neutralizing  the  acid  of  the  iron  upon  the 
goods,  which,  as  a  salt,  would  act  upon  the  logwood,  and  injure 
the  operation.  Washing  out  of  the  copperas  answers  equally 
well,  and  for  fine  goods,  where  a  soft  tint  of  black  is  necessary, 
is  even  preferable.  When  the  goods  are  passed  through  the 
lime,  the  presence  of  the  alkali  is  hurtful  to  the  logwood  ;  there- 
fore it  is  best  to  pass  the  goods  through  water  before  entering 
tl^m  into  the  logwood.  The  action  of  the  iron  upon  this  sub- 
stance is  the  same  as  we  have  described  for  galls ;  a  persalt  of 
iron,  added  or  used,  gives  an  immediate  black,  but  not  perma- 
nent; the  oxygen  seeming  to  affect  the  decomposition  of  the 
color  in  some  way.  When  a  protosalt  of  iron,  as  copperas,  is 
used,  the  blackening  is  slower,  but  more  permanent ;  showing 
that  it  is  the  most  suitable  salt  to  use.  It  is,  however,  to  be 
remarked,  that  the  combination  of  iron  and  tannin,  forming  the 
black  color,  seems  to  depend  on  a  state  of  oxidation  of  the  iron 
a  little  higher  than  the  protoxide,  and  much  lower  than  the 
peroxide ;  that  the  peroxide,  when  used,  is  reduced  in  oxida- 
tion, and  causes  change  and  loss  in  reduction,  and  that  the 
protoxide  imbibes  oxygen  as  required*  Upon  this  important 
inquiry  we  quote  the  following  from  an  article  by  M.  Barreswil 
in  the  Chemical  Gazette,  translated  from  the  Comptes  Bendus  : — 

"  When  a  solution  of  gallic  or  of  tannic  acid,  which  are 
colorless,  and  generally  form  colorless  salts  or  of  the  color  of 
the  bases,  is  poured  into  a  solution  of  the  persulphate  of  iron, 
an  intense  blue  precipitate  is  formed,  which  remains  suspended 
in  the  liquid.  This  anomalous  fact  has  frequently  excited  the 
attention  of  chemists;  MM.  Berzelius  and  Chevreul  have  even 
expressed  some  doubts  respecting  the  simplicity  of  the  reaction. 

"  It  has  long  been  known  that  tannin  and  gallic  acid  do  not 


*An  opinion  urged  several  years  ago  by  the  author  in  the  Practical 
Mechanics'  and  Engineers'  Magazine. 


252 


SUMACH. 


precipitate  the  protosalts  of  iron  when  protected  from  contact 
with  the  atmosphere.  Berzelius,  Chevreul,  and  Persoz  have, 
moreover,  observed  that  when  gallic  acid  or  tannin  is  conveyed 
into  a  salt  of  the  peroxide  of  iron,  it  is  always  reduced  to  the 
state  of  a  protosalt.  This  fact  is  easily  proved  by  adding  to 
the  blue  solution  produced  by  the  persulphate  of  iron  in  a 
solution  of  gallic  acid,  an  excess  of  acetate  of  lead  or  of  carbo- 
nate of  lime,  which  precipitates  the  blue  combination,  and  at 
the  same  time  the  sulphuric  acid.  A  colorless  liquid  is 
separated  by  filtration,  in  which  the  presence  of  iron  may  be 
demonstrated  in  the  state  of  protoxide. 

"  These  experiments  are  insufficient  to  explain  this  curious 
reaction.  It  is  not  improbable  to  admit,  as  MM.  Berzelius  and 
Chevreul  have  done  d  priori,  that  the  oxygen  combining  with 
the  gallic  acid  or  the  tannin  converts  them  into  a  new  acid  of 
a  blue  color ;  but  positive  experiments  were  wanting  to  decide 
the  point. 

"When  a  solution  of  tannin  or  of  gallic  acid  is  poured  by 
drops  into  a  solution  of  persulphate  of  iron  in  excess,  no  blue 
coloring  is  obtained;  if  there  is  one  produced  it  is  only  mo- 
mentary. Nor  is  there  one  formed  with  the  same  salt  in  mifi- 
mum  in  presence  of  chlorine,  nor  with  a  protosalt  of  iron  and 
gallic  acid  oxidized  in  various  degrees  by  chlorine,  by  a  salt  of 
silver,  or  lastly,  by  the  atmosphere  in  an  alkaline  solution. 

"  When  a  solution  of  gallic  acid  in  excess  is  conveyed  into 
persulphate  of  iron,  and  the  liquid  thrown  down  by  acetate  of 
lead,  a  blue  paste  is  obtained,  which,  treated  with  oxalic  acid, 
forms  soluble  oxalate  of  iron ;  the  blue  color  disappears  en- 
tirely, and  is  restored  by  acetate  of  soda.  The  solution  of  the 
oxalate,  diluted  very  much  with  water,  treated  cautiously  with 
the  two  prussiates  and  sulphureted  hydrogen,  presents  all  the 
characters  of  the  salts  of  iron  in  the  state  of  peroxide  and 
protoxide. 

"  It  appears  to  me  that  we  may  conclude  from  the  above 
facts  that,  if  we  start  with  a  protosalt  of  iron,  it  is  requisite  to 
add  oxygen,  and,  if  we  set  out  with  a  persalt,  some  oxygen 
must  be  removed,  in  order  to  produce  the  blue  compound,  and 
that  this  compound  contains  the  two  oxides.  In  the  first  case 
the  protoxide  of  iron  combines  with  the  oxygen  of  the  atmos- 
phere ;  in  the  second,  a  portion  of  the  oxygen  of  the  peroxide 
destroys  a  corresponding  portion  of  the  gallic  acid  or  of  the 
tannin,  converting  it  into  a  brown  substance.  This  substance 
does  not  enter  into  the  constitution  of  the  new  compound, 
which  must  be  considered  as  a  salt  formed  of  tannin  or  gallic 
acid  and  of  an  intermediate  oxide  of  iron,  probably  of  a  blue 


SUMACH. 


253 


color,  the  tint  of  which  is  slightly  altered  by  this  brown  sub- 
stance. 

"To  prove  in  the  most  evident  manner  that  the  blue  coloring 
is  not  to  be  ascribed  to  a  blue  acid,  but  to  a  particular  oxide, 
I  endeavored  to  obtain  other  blue  salts  with  mineral  acids,  for 
instance  with  sulphuric  acid.  For  this  purpose  I  prepared 
some  mixtures  in  variable  proportions  of  the  protosulphate  of 
iron  and  of  the  persulphate,  and  to  avoid  an  inevitable  separa- 
tion of  the  two  salts  from  their  different  degrees  of  solubility. 
I  removed  immediately  the  water  by  adding  to  the  solution 
concentrated  sulphuric  acid  in  large  excess,  taking  care  to  pro- 
duce &s  little  heat  as  possible.  In  this  manner  I  obtained  a 
thick  paste  of  a  deep  blue,  the  tint  of  which  was  more  or  less 
pure  according  to  the  proportions  of  the  two  salts  of  iron  ;  I 
likewise  produced  a  blue  sulphate,  but  of  very  ephemerous 
existence,  by  evaporating  rapidly  a  mixture  of  the  two  salts  of 
iron;  the  blue  tint  appeared  at  the  moment  when  the  mass  was 
nearly  dry.  On  substituting  phosphate  of  soda  for  the  sulphuric 
acid,  I  obtained  a  deep-blue  phosphate  of  iron  and  some  sul- 
phate of  soda,  wThich  removed  the  water  immediately.  I  en- 
deavored, but  without  success,  to  prepare  combinations  with 
other  salts;  the  hyposulphite  of  soda  alone  afforded  an  intense 
blue  coloring,  but  of  remarkable  instability.  This  is  not  sur- 
prising; there  are  many  instances  in  chemistry  of  bases  which 
prefer  combining  with  certain  acids  and  refuse  to  unite  with 
others;  such,  for  instance,  among  others,  is  the  protoxide  of 
copper. 

"I  made  numerous  experiments  to  obtain  the  blue  oxide  in 
a  free  state  ;  I  succeeded  several  times,  but  under  circumstances 
which  I  was  not  able  to  produce  at  will.  It  is,  however,  a  well- 
known  fact  that,  when  a  protosalt  of  iron  is  precipitated  with 
ammonia  in  contact  with  the  atmosphere,  the  white  precipitate 
of  the  protoxide  soon  becomes  green,  passing  first,  however, 
through  blue. 

"  The  impossibility  of  obtaining  the  blue  sulphate  of  iron 
in  a  crystalline  state,  and  of  isolating  the  acid  of  the  blue  gal- 
late  compound,  prevented  me  from  having  recourse  to  analysis 
in  order  to  arrive  at  the  formula  for  these  intermediate  salts; 
I  was  forced  to  proceed  by  synthesis,  which,  I  confess,  is  far 
from  being  accurate ;  and  it  is  with  some  doubts  that  I  publish 
the  results. 

"Of  all  the  mixtures  of  protosulphate  and  persulphate 
which  I  experimented  on,  that  which  afforded  the  most  pure 
blue  with  sulphuric  and  gallic  acids  and  with  the  phosphate  of 
soda,  contained  precisely  3  equivalents  of  protosalt  to  2  of  the 


254 


CATECHU. 


persalt — proportions  which  correspond  to  the  cyanide  Fe7  Og, 
prussian  blue. 

"  If,  as  I  hope,  I  have  rendered  probable  the  existence  of 
two  intermediate  oxides  of  iron,  capable  of  forming  salts  and 
of  entering  into  the  salts  with  their  peculiar  color,  I  shall  have 
thrown  some  light  on  the  various  tints  produced  by  the  differ- 
ent kinds  of  astringent  substances,  morphine,  salicylic  acid, 
and  some  other  organic  principles ;  and  likewise  on  the  pro- 
duction of  violet,  black,  brown,  and  green  tints,  with  red  and 
yellow-coloring  principles,  in  presence  of  salts  of  peroxide  of 
iron.  I  have  convinced  myself  that  all  the  yellow-coloring 
substances  (for  instance  curcuma)  do  not  produce  green  ;  that 
the  red-coloring  principles  (among  others  aloetic  acid)  do  not 
give  a  violet ;  and  that  when  there  is  a  production  of  green  (as 
with  the  Persian  berries  and  the  Quercitron),  or  of  violet  (as 
with  madder,  logwood,  &c),  the  phenomena  are  identical  with 
those  which  occur  with  tannin  and  gallic  acid.  These  obser- 
vations agree,  moreover,  perfectly  with  the  suppositions  of  M. 
Thenard,  with  the  facts  published  by  M.  Koechlin-Schouch,  and 
by  M.  Schlumberger,  and  which  M.  Stackler  informs  me  he 
has  found  confirmed  in  his  establishment,  that  the  iron  mor- 
dants should  be  at  a  fixed  degree  of  oxidation  to  produce  beau- 
tiful dyes." — Comptes  Bendus. 

Catechu. 

This  is  another  substance  containing  much  tannin.  We 
have  already  noticed  some  of  its  peculiarities,  but  may  state 
further  that  it  is  a  dry  extract  prepared  from  the  wood  of  a 
species  of  sensitive  plant,  named  acacia  catechu.  It  was  long 
considered  an  earthy  substance,  and  termed  terra  Japonica. 
The  plant  is  indigenous  to  Hindostan,  and  flourishes  abundantly 
in  mountainous  districts.  It  grows  to  about  twelve  feet  in 
height;  the  trunk  is  about  a  foot  in  diameter,  and  covered  with 
a  thick  dark-brown  bark.  The  extract  which  is  obtained  from 
the  tree  is  made  from  a  decoction  of  the  wood.  As  soon  as 
the  trees  are  felled,  all  the  exterior  white  wood  is  carefully  cut 
away,  the  interior,  or  colored  wood,  is  then  cut  into  chips ; 
narrow-mouthed  unglazed  pots  are  nearly  filled  with  these,  and 
water  is  added  to  cover  them.  Heat  is  applied,  and  when  half 
the  water  is  evaporated,  the  decoction,  without  straining,  is 
poured  into  a  shallow  earthen  vessel,  and  farther  reduced  two- 
thirds  by  boiling.  It  is  then  set  in  a  cool  place  for  a  day,  and 
is  afterwards  evaporated  by  the  heat  of  the  sun,  care  being 
taken  to  stir  it  occasionally  during  that  process.    When  it  is 


CATECHU. 


255 


reduced  to  considerable  thickness  it  is  spread  upon  a  mat  or 
cloth,  which  has  been  previously  covered  with  the  ashes  of 
cow-dung,  and  this  mass  divided  by  a  string  into  quadrangular 
pieces,  is  completely  dried  in  the  sun,  and  is  then  fit  for  sale. 

It  is  a  brittle  compact  substance,  of  a  dark-brown  or  choco- 
late color;  has  no  smell,  but  a  very  astringent  taste;  is  soluble 
in  water;  contains  a  great  amount  of  tannin,  and  a  peculiar 
acid,  which  has  been  named  catechuic  acid.  It  is  the  reactions 
of  these  ingredients  with  oxygen  and  other  chemical  agents, 
that  constitute  its  dyeing  properties.  A  solution  of  catechu 
in  water  is  a  beautiful  reddish-brown  color,  which  ought  to  be 
kept  in  miud  in  perusing  the  following  summary  of  the  re- 
actions of  other  substances  upon  it : — 

Acids  brighten  the  color  of  the  solution  ;  alkalies  darken  it, 
and  the  shade  deepens  by  standing;  protosalts  of  iron  give 
olive-brown  precipitates  ;  persalts  of  iron  also  give  olive  brown 
precipitates,  but  with  more  green  than  those  of  the  protosalts ; 
salts  of  tin  give  yellowish-brownish  precipitates;  nitrate  and 
sulphate  of  copper,  yellowish-brown  ;  acetate  of  copper,  a 
brown  precipitate;  salts  of  lead,  brick-colored  precipitates; 
bichromate  of  potash,  a  deep  red  brown.  These  reactions  alone 
indicate  how  very  important  an  agent  catechu  may  be  in  the 
hands  of  the  dyer,  and  how  very  extensive  its  applications  in 
the  processes  of  his  art. 

There  are  various  qualities  of  catechu  in  the  market,  differ- 
ing considerably  in  their  value  as  a  dye.  The  Bombay  catechu 
is  met  with  in  square  masses,  of  reddish  brown  color,  and 
which,  when  broken,  exhibit  a  uniform  texture.  Its  composi- 
tion is  as  follows: — 


"  Extractive  matter"  is  a  sort  of  indefinite  term,  applied  to 
designate  a  brown  matter  extracted  from  vegetables  when 
boiled;  its  true  nature  is  not  known,  but  the  part  it  may  play 
in  the  reactions  of  catechu  is  probably  important,  and  is  at 
least  not  to  be  overlooked. 

Bengal  catechu  is  met  with  in  flattish  round  lumps,  of  a 
light  brown  color  outside,  but  dark  internally.    It  gives: — 


Tannin .... 
Gum  .... 

Extractive  matter 
Impurities     .•  . 


52 
7 

34 
7 


100 


256 


CATECHU. 


Tannin   49.5 

Gum   7.0 

Extractive  matter   36.5 

Impurities   7.0 


100.0 

Malabar  catechu  is  imported  in  large  masses,  of  a  light- 
brown  color  outside,  dark  within,  and  covered  with  leaves.  It 


gives: — 

Tannin   45.8 

Gum   8.0 

Extractive  matter   39.9 

Impurities   6.3 


100.0 

There  is  a  sort  of  catechu  brought  to  this  country  from 
India  in  small  cubical  masses,  about  an  inch  in  size.  This  is 
a  very  inferior  quality,  and,  as  imported,  is  easily  known  from 
genuine  catechu.  Sometimes,  however,  means  are  resorted  to 
to  alter  the  color  of  this  spurious  article,  and  make  it  more 
difficult  to  be  detected.  It  is  often  said  to  contain  a  great 
quantity  of  roasted  starch,  or  British  gum,  termed  dextrine. 

Catechu  is  often  adulterated  by  other  vegetable  extracts, 
and  also  by  sand,  clay,  and  ochre.  These  last  impurities  may 
be  readily  detected  by  dissolving  a  portion  of  the  catechu  in 
water,  when  any  of  them  contained  in  it  will  be  precipitated ; 
or  by  burning  a  little  of  it  in  a  crucible  until  all  organic  mat- 
ter is  consumed,  when  the  latter  adulterants  will  remain.  We 
have  examined  samples  of  catechu  of  good  color,  having  8J 
per  cent,  of  clay  and' sand  mixed  with  them.  Good  catechu  is 
all  soluble  in  cold  water,  and  gives  a  clear  solution. 

The  tannin  which  is  in  catechu  is  not  converted  into  gallic 
acid  by  exposure  so  easily  as  that  in  galls;  but  it  is  subject  to 
oxidation.  When  a  portion  is  dissolved  in  water,  the  solution 
has  a  gummy  character,  and  goods  put  into  it  would  be  affected 
as  by  a  weak  solution  of  gum  ;  the  threads  of  yarn,  for  exam- 
ple, adhere  when  dried  out  of  it.  The  addition  of  a  metallic 
salt  destroys  this  vicious  quality,  and  those  salts  answer  best, 
or  are  most  effectual  for  that  purpose,  which  yield  their  oxygen 
most  easily.  Accordingly  the  salts  of  copper  are  most  com- 
monly used,  and  they  are  added  to  the  dissolved  catechu  before 
putting  in  the  cotton.  The  chemical  changes  which  catechu 
undergoes  in  the  operations  of  dyeing  are  not  yet  well  under- 
stood.   The  action  has  been  explained  in  this  way :  The 


CATECHU. 


257 


copper  salt  oxidizes  a  portion  of  the  catechu,  which,  although 
insoluble  in  water,  is  soluble  in  deoxidized  catechu,  therefore 
the  whole  is  held  in  solution  in  the  bath;  the  goods  become 
impregnated  with  this  solution,  and  as  the  whole  of  the  catechu 
upon  the  cloth  becomes  oxidized,  it  becomes  also  dark.  This 
explanation  does  not  account  for  all  the  phenomena  occurring 
during  the  dyeing  of  browns,  &c,  with  this  substance;  for  if 
we  take  two  portions  of  a  solution  of  catechu,  and  to  the  one 
add  a  salt  of  copper,  to  the  other  a  salt  of  zinc,  pass  the  cloth 
from  these  through  a  solution  of  lime  and  expose  to  the  air, 
the  piece  treated  with  the  zinc  will  become  dark  brown,  but 
not  that  treated  with  the  copper.  The  above  explanation 
would  lead  us  to  expect  the  opposite,  as  copper  yields  its  oxy- 
gen more  easily  than  zinc.  When  catechu  is  oxidized,  there 
is  formed  an  acid  nearly  of  the  composition  of  gallic  acid, 
which  has  a  deep  brown  color.  This  is  formed  when  catechu 
in  solution  is  treated  with  alkaline  matters.  The  lime,  there- 
fore, in  the  above  experiment  may  have  acted  the  principal 
part;  but  cotton  from  catechu  solution,  put  through  acetate 
of  lead,  also  gives  a  deep  brown  color  without  alkali.  When 
goods  impregnated  with  catechu  are  passed  through  bichro- 
mate of  potash,  there  is  obtained  a  deep  brown ;  an  oxidation 
of  the  catechu  takes  place  at  the  expense  of  the  chromic  acid. 
Whether  the  oxide  of  chromium  may  act  as  a  base  on  any 
part  of  the  dye,  we  cannot  positively  affirm;  but  on  burning 
cotton  dyed  brown  by  this  means,  there  is  obtained  in  the  ash 
the  oxides  both  of  chrome  and  of  copper;  showing  that  both 
the  copper  and  chrome  used  play  a  part  in  forming  the  dye, 
and  that  the  dye  by  this  method  is  something  more  than  mere 
oxidation  of  the  catechu,  as  in  passing  the  cloth  from  the 
catechu  through  bleaching  liquor. 

The  reactions  of  catechu  are  so  varied,  that  it  is  now  used 
for  almost  all  compound  colors,  blacks,  browns,  greens,  drabs, 
and  fawns  ;  and  its  permanency  renders  it  of  high  estimation  in 
'the  market. 

The  following  is  the  analysis  of  a  sample  of  catechu  by  Mr. 
Cooper,  giving  a  wider  range  to  the  matters  contained  in  it,  and 
which  will  serve  to  give  some  better  idea  of  the  varieties  of  this 
substance;  for  from  its  mode  of  preparation,  probably  no  two 
samples  will  give  the  same  proportions: — 


17 


258        VEGETABLE  SUBSTANCES  CONTAINING  TANNIN. 


Resinous  matter 
Gummy  matter 
Insoluble  matter 
Water    .    .  . 


Tannin  

Extractive,  or  coloring  matter  . 


62.8 
8.2 
2.0 
8.5 
4.4 

12.3 


98.2 


Valonia  Nuts. — These  are  the  cups  of  the  acorn  from  the 
valonia  oak,  which  grows  in  the  Dardanelles  and  the  islands  of 
the  Archipelago,  and  throughout  all  the  maritime  ports  of  Asia 
Minor.  They  are  imported  in  great  quantities  from  Smyrna 
and  its  neighborhood.  These  contain  a  great  quantity  of  tannin, 
and  also  gallic  acid  ;  'but  they  are  inferior  to  sumach  or  galls  for 
dyeing  cotton,  and  for  giving  depth  of  color  with  the  salts  of 
iron.  For  silk,  however,  they  possess  some  peculiarities 
exceedingly  valuable  for  blacks,  giving  a  permanency  not  ob- 
tained with  the  ordinary  galls;  and,  moreover,  the  production 
of  the  proper  black  with  valonia  nuts  upon  silk  requires  a  cer- 
tain treatment  which  few  dyers  have  attained,  particularly  in 
Scotland.  We  cannot,  for  instance,  furnish  a  black  upon  silk 
which  will  withstand  unchanged  all  the  operations  which  a  hat 
undergoes  in  the  process  of  manufacture — a  purpose  for  which 
we  understand  the  valonia  black  is  applied. 

Divi  Divi,  or  Libi  Davi,  is  the  pod  of  a  leguminous  shrub,  a 
native  of  South  America;  it  has  been  tried  as  a  dye  instead  of 
galls  or  sumach,  but  is  not  much  used,  now,  if  at  all. 

Myrobalans. — This  is  the  fruit  of  a  tree  which  grows  in 
India  ;  it  is  imported  into  this  country  in  various  forms,  has  a 
pale  yellow  color  when  new,  but  becomes  darker  by  age,  and 
then  resembles  dried  plums.  It  contains  tannin,  and  is  some- 
times used  on  that  account  for  the  operations  of  dyeing.  Its 
reactions  with  iron,  tin,  and  alum,  are  similar  to  those  of  sumach, 
but  of  less  value. 

Oak  bark  contains  a  great  quantity  of  tannin,  and  is  used 
on  that  account  for  tanning  skins,  but  it  is  not  much  employed 
in  the  dye-house,  although  it  may  be  used  for  similar  purposes 
as  sumach.  The  bark  of  the  mangrove  tree  also  contains 
tannin  in  considerable  quantity;  there  are,  indeed,  very  few 
vegetables  which  have  not  in  their  composition  more  or  less 
of  tannin,  and  which  may  not  be  used  in  virtue  of  this  property 
instead  of  galls  or  sumach ;  but  the  quantity  in  them  being 
much  less  than  in  sumach,  they  are  not  cultivated  for  that  pur- 
pose. The  bark  of  the  ash,  willow,  hazel,  birch,  broom,  &c, 
are  often  used  for  dyeing  woollens  by  country  people  ;  and 


TESTS  FOR  TANNIN. 


259 


some  of  these  substances  possess  peculiar  dyeing  properties. 
The  husks  of  several  nuts  also  contain  much  tannin.  The 
walnut,  for  instance,  has  long  been  used  and  much  esteemed 
by  the  French  dyers  for  woollen  stuffs  ;  it  gives  very  fast  shades, 
without  previous  mordanting,  although  alum  is  sometimes  used 
to  give  variety.  The  outer  peel  of  this  nut  is  collected  for  the 
dyers;  they  are  put  into  large  casks,  with  water  poured  over 
them,  and  kept  for  a  year  or  more,  as  they  improve  while  this 
process  of  maceration  is  prolonged.  The  roots  of  the  walnut 
tree  are  also  used  for  dyeing  browns.  The  husks  of  the  horse- 
chestnut  likewise  possess  dyeing  qualities,  and  might  be  ap- 
plied "advantageously  for  some  purposes.  Mahogany  sawdust, 
although  not  affected  much  by  mordants,  possesses  dyeing 
properties  of  considerable  value,  yielding  with  iron  a  variety 
of  shades  of  great  permanence  and  beauty. 

Many  of  the  dye-woods  which  are  used  for  their  coloring 
matter  contain  tannin,  the  action  of  which  upon  the  mordants 
is  often  very  injurious  to  the  tint.  Many  varieties  of  the  dif- 
ferent woods,  giving  the  same  color,  depend  much  upon  the 
presence  of  tannin.  The  whole  woody  matter  being  boiled  to 
extract  the  coloring  matter,  the  tannin  is  also  dissolved,  and  it 
is  sure  to  act  upon  the  mordant  in  the  process  of  dyeing,  pro- 
ducing an  effect  very  similar  to  that  of  adding  a  little  sumach 
to  the  coloring  matter.  In  many  cases  this  is  done  beneficially, 
but  in  other  cases  it  would  deteriorate  the  tint  required.  In 
such  cases  the  presence  of  tannin  in  the  coloring  matter  obtained 
from  the  wood  does  not  suit.  Mr.  Warrington  proposed  as  a 
practical  means  of  ascertaining  the  quantity  of  tannin  in  any 
matter,  the  following  test :  Premising  that  a  solution  of  gelatin, 
isinglass,  or  glue  precipitates  tannin  ;  making  a  given  quantity 
of  this  solution  by  adding  drop  by  drop  to  a  given  quantity  of 
the  substance  to  be  tested  for  tannin,  also  in  solution,  as  long 
as  a  precipitate  is  formed,  and  marking  in  the  alkalimeter  the 
quantity  of  gelatin  used  ;  every  three  grains  of  pure  gelatin  is 
equal  to  two  grains  tannin,  and  accordingly  it  is  easy  to  arrive 
at  a  near  approximation  of  the  quality  of  these  dyestuffs.  This 
operation  will,  no  doubt,  require  a  little  experience,  but  it  is 
easily  performed,  and  well  deserves  attention. 


260 


INDIGO. 

In  the  few  introductory  remarks  we  made  upon  vegetable 
colors,  we  mentioned  that,  besides  the  green  of  leaves  and  the 
colors  of  flowers,  which  we  considered  common  to  all  vegeta- 
bles, there  were  other  coloring  matters,  which  existed  only  in 
certain  kinds  of  vegetables,  and  in  particular  parts  of  the  vege- 
table. Indigo  is  one  of  these ;  it  belongs  to  a  genus  of  legu- 
minous plants  found  in  India,  Africa,  and  America,  named 
indigofera.  Botanists  have  described  about  sixty  species  of 
this  genus.  These  all  yield  indigo;  but  the  species  from  which 
it  is  usually  extracted  are  the  /.  anil.,  the  /.  argentea,  and  the 
/.  tinctoria.  It  is  also  extracted  from  a  tree  very  common  in 
Hindostan  (the  nerium  tinctorivm  of  botanists),  and  from  the 
woad  plant  (isatis  tinctoria),  which  is  a  native  of  Great  Britain, 
and  of  other  parts  of  Europe.  The  coloring  matter  of  these 
plants  is  wholly  in  the  cellular  tissue  of  the  leaves,  as  a  secre- 
tion, or  juice,  not,  however,  in  the  blue  state  in  which  we  are 
accustomed  to  see  indigo,  but  as  a  white  substance,  which,  as 
we  shall  presently  see,  remains  white,  so  long  as  the  tissue  of 
the  leaf  remains  perfect.  When  this  tissue  is  by  any  means 
destroyed,  the  indigo  absorbs  oxygen  from  the  atmosphere  and 
becomes  blue. 

Of  the  early  history  of  indigo  little  is  known  ;  neither  is  it 
known  when  it  was  first  used  as  a  dyestuff.  The  Greeks  and 
Eomans  used  it  as  a  paint  under  the  name  of  indicum.  Its 
value  as  a  dyestuff'  was  not  known  in  Europe  till  nearly  the 
close  of  the  sixteenth  century,  when  it  was  imported  from  India 
by  the  Dutch;  but  our  legislators,  for  a  long  time,  prohibited 
its  use  in  England  under  severe  penalties.  These  prohibitions 
continued  in  force  till  the  reign  of  Charles  II.,  and  the  reason 
assigned  was  that  it  is  a  corrosive  substance,  destructive  of  the 
fibres  of  the  cloth,  and  therefore  calculated  to  injure  the  cha- 
racter of  the  dyers  of  this  country.  This  opinion,  no  doubt, 
sprung  from  the  strong  and  interested  opposition  to  its  use  by 
the  cultivators  of  the  woad,  which  was  then  regarded  as  an 
important  branch  of  national  industry. 

"When  indigo  was  first  introduced,  only  a  small  quantity 
was  added  to  the  woad,  by  which  the  latter  was  much  im- 
proved; more  was  afterwards  gradually  used,  and,  at  last,  the 
quantity  became  so  large,  that  the  small  admixture  of  woad 
served  only  to  revive  the  fermentation  of  the  indigo.  Ger- 


MANUFACTURE  OF  INDIGO. 


261 


many  thus  lost  a  production  by  which  farmers,  merchants, 
carriers,  and  others,  acquired  great  riches.  In  consequence  of 
the  sales  of  woad  being  so  much  injured,  a  prohibition  was 
issued  against  the  use  of  indigo  in  Saxony,  in  the  year  1650; 
and  in  the  year  1652,  Duke  Ernest  the  Pious  caused  a  proposal 
to  be  made  to  the  diet  by  his  envoy,  that  indigo  should  be 
entirely  banished  from  the  empire,  and  that  an  exclusive  privi- 
lege should  be  granted  to  those  who  dyed  with  woad.  This 
was  followed  by  an  imperial  prohibition  of  indigo  on  the  21st 
of  April,  1654,  which  was  enforced  with  the  greatest  severity 
in  his  dominions.  The  same  was  done  in  France;  but  in  the 
well-known  edict  of  1669,  in  which  Colbert  separated  the  fine 
from  the  common  dyers,  it  was  stated,  that  indigo  should  be 
used  without  woad,  and  in  1737,  dyers  were  left  at  liberty  to 
use  indigo  alone,  or  to  employ  a  mixture  of  indigo  and  woad." 
— Barloitfs  Manufactures  and  Machinery  of  Great  Britain. 

The  plant  which  yields  the  indigo  in  Bengal  is  a  small 
straight  plant  furnished  with  thin  branches,  which  spread  out 
and  form  a  sort  of  tuft;  the  average  height  is  four  feet,  but  on 
good  ground  it  sometimes  attains  a  height  of  even  seven  feet. 
The  leaves  are  soft,  and  somewhat  like  those  of  the  common 
clover,  and  the  blossoms  are  of  a  light-reddish  color.  The  plant 
is  at  its  greatest  perfection,  and  yields  the  greatest  quantity  of 
indigo,  when  in  full  blossom. 

There  are  two  methods  of  extracting  the  coloring  matter 
from  the  leaves :  the  first  is  by  fermentation  and  beating.  This 
process  is  conducted  in  two  large  brick  cisterns  or  vats,  built 
in  relation  to  one  another,  like  two  steps  of  a  stair.  The  upper 
one  is  termed  the  steeper,  because  in  it  the  fermentation  is 
conducted.  At  the  bottom  of  this  cistern  there  is  a  plug-hole 
through  which,  when  the  process  of  fermentation  is  finished, 
the  fluid  is  run  off  into  the  lower  cistern,  denominated  the 
beater,  because  in  it  the  process  of  beating  the  fluid  by  paddles, 
to  separate  the  fecula  from  the  water,  is  performed.  The  plant, 
when  cut,  is  tied  up  in  bundles  about  five  feet  in  circumference, 
and  conveyed  as  quickly  as  possible  to  the  vat;  for,  were  it 
kept  but  a  short  time  in  heaps,  the  indigo  in  the  plant  would 
be  destroyed.  The  upper  vat  is  filled  to  about  five  or  six  inches 
from  the  top  with  these  bundles  laid  in  regular  tiers.  To  pre- 
vent the  throwing  up  of  the  herb  by  the  swelling  and  agitation 
caused  by  the  fermentation,  there  are  irons  built  in  the  two  side 
walls,  opposite  to  one  another,  to  which  are  fastened  beams  of 
wood,  which  traverse  the  whole  length  and  breadth  of  the  vats. 
When  the  vat  is  sufficiently  filled  with  the  vegetable,  a  strong 
grating  of  bamboo,  large  enough  to  cover  the  whole  surface,  is 
laid  over  the  plant,  and  fastened  down  by  the  cross-beams. 


262 


INDIGO. 


These  precautions  being  completed,  cold  water  is  poured  as 
quickly  as  possible  into  the  vat,  till  the  surface  rises  within 
three  or  four  inches  of  the  upper  edges.  In  a  short  time  fer- 
mentation commences,  and  is  completed  in  from  nine  to  twelve 
hours.  Towards  the  end,  the  action  is  very  brisk,  swelling  and 
throwing  up  frothy  bubbles,  which  sometimes  rise  like  pyra- 
mids. These  bubbles  are  white  at  first,  but  after  a  little  expo- 
sure to  the  air,  they  become  blue,  and  then  purple.  This  part 
of  the  operation  requires  great  skill.  If  the  fermentation  be  too 
long,  the  indigo  will  be  much  damaged  ;  and,  if  too  short,  the 
quantity  is  much  diminished.  When  the  liquor  ceases  to  swell \ 
it  is  let  out  into  the  second  or  beating  vat,  and  is  then  of  a 
light-green  color. 

The  liquor  being  now  in  the  lower  or  beating  vat,  a  number 
of  men  enter  it,. furnished  with  oar-shaped  paddles,  about  four 
feet  in  length ;  they  continue  to  walk  backwards  and  forwards, 
agitating  or  beating  the  liquor  with  these  paddles.  At  the  com- 
mencement of  this  agitation,  the  liquor  begins  to  froth;  but 
this  is  prevented,  provided  the  fermentation  has  not  gone  on 
too  long,  by  a  few  drops  of  oil.  In  the  course  of  an  hour  and 
a  half,  the  liquor  begins  to  granulate,  and  assume  the  appear- 
ance of  agitated  water,  full  of  wood  grounds  or  sawdust  This 
part  of  the  process  also  requires  considerable  care  and  manage- 
ment; for,  if  the  beating  be  stopped  too  soon,  the  indigo  will 
not  be  all  separated  from  the  liquor,  occasioning  a  proportionate 
loss ;  if  continued  too  long,  the  granulated  particles  are  broken, 
and  dispersed  through  the  liquor,  and  do  not  readily  fall  to  the 
bottom.  When  the  beating  is  completed,  the  vat  is  allowed  to 
settle ;  the  grains  which  constitute  the  indigo  fall  to  the  bottom, 
and  the  supernatant  liquor  is  let  off*  by  plug-holes  in  the  side 
of  the  vat.  The  precipitate  is  then  removed  to  a  copper  boiler, 
to  which  there  is  a  fire  kept  till  the  liquor  becomes  as  thick  as 
oil.  Some  manufacturers  bring  it  to  this  state  by  causing  the 
liquor  to  boil;  others  by  keeping  it  at  a  moderate  temperature. 
The  former  process  produces  lighter  indigo  than  the  latter.  In 
this  state  it  is  put  into  a  large  flat  vessel,  furnished  at  the  one 
end  with  a  cloth  filter.  After  most  of  the  liquor  has  filtered 
through,  the  indigo  remains  in  the  vessel  about  the  consistence 
of  butter.  It  is  then  put  on  proper  frames,  and  subjected  to 
considerable  pressure  by  a  sort  of  screw-press ;  and  is  now  ready 
to  be  cut  into  small  cakes,  which  are  placed  upon  boards  in  a 
drying  stove;  when  dry,  these  cakes  are  packed  up,  and  in 
this  state  form  the  indigo  of  commerce. 

The  other  method  of  extracting  the  indigo  from  the  plant 
differs  from  that  described,  only  in  the  first  operations.  In- 
stead of  putting  the  plant  into  the  vat  when  newly  cut,  it  is 


MANUFACTURE  OF  INDIGO. 


2H3 


spread  out,  to  dry  in  the  sun  for  two  days,  and  then  thrashed 
to  separate  the  leaves  from  the  stems.  The  leaves  are  then 
kept  until  they  have  changed  from  a  green  to  a  bluish  gray, 
or  lavender  color;  they  are  then  put  into  the  first  vat  with 
warm  water,  and  kept  stirring  till  the  leaves  are  so  completely 
wetted  as  to  sink.  The  liquor  is  then  instantly  let  off  into  the 
beating  vat,  where  it  is  treated  as  already  described. 

The  chemical  changes  which  take  place  during  these  opera- 
tions are  not  well  understood,  and  the  various  opinions  ex- 
pressed by  chemists  concerning  them  are  not  very  easily  recon- 
ciled. Berthollet,  in  his  Elements  of  Dyeing,  while  describing 
the  process  of  the  first  or  fermenting  vat,  says:  u  In  the  first  a 
fermentation  is  excited,  in  which  the  action  of  the  atmospheric 
air  does  not  intervene,  since  an  inflammable  gas  is  evolved. 
There  probably  results  from  it  some  change  in  the  composition 
of  the  coloring  particles  themselves,  but  especially  the  separa- 
tion or  destruction  of  a  yellowish  substance,  which  gave  to  the 
indigo  a  greenish  tint,  and  rendered  it  susceptible  of  suffering 
the  chemical  action  of  other  substances.  This  species  of  fer- 
mentation passes  into  a  destructive  putrefaction,  because  the 
indigo,  as  we  shall  see,  has  a  composition  analogous  to  that  of 
animal  substances." 

Dr.  Ure,  in  his  Dictionary  of  the  Arts  and  Manufactures,  says, 
that  from  some  experiments  made  upon  the  gases  given  off 
during  fermentation,  they  were  found  to  be  composed,  when 
taken  about  the  middle  of  the  operation,  of  27.5  of  carbonic 
acid  gas,  5  8  of  oxygen,  and  66.7  of  nitrogen,  in  the  100  parts  ; 
and  towards  the  end  of  the  operation,  they  consisted  of  40.5  of 
carbonic  acid  gas,  4.5  of  oxygen,  and  55  of  nitrogen.  No  car- 
bureted hydrogen  is  disengaged.  "  The  fermenting  leaves," 
using  the  Doctor's  words,  "  apparently  convert  the  oxygen  of 
the  air  into  carbonic  acid,  and  leave  its  nitrogen  free.  They 
also  evolve  a  quantity  of  carbonic  acid  spontaneously.  It  will 
be  observed  that  these  two  opinions  are  decidedly  contradictory  ; 
the  one  says  that  the  action  of  the  atmosphere  does  not  inter- 
vene, and  that  an  inflammable  gas  is  evolved ;  the  other,  that 
there  is  no  inflammable  gas  evolved,  and  that  the  air  is  appa- 
rently the  principal  agent  in  effecting  the  various  changes. 
But  when  we  recollect  that  the  leaves  are  all  under  the  liquor, 
and  kept  so  by  the  fixed  position  of  the  beams,  there  can  be 
little  contact  between  the  fermenting  leaves  and  the  air,  except 
that  held  by  the  water,  and  among  the  leaves,  and  of  the  plants 
themselves ;  hence  the  conversion  of  its  oxygen  into  carbonic 
acid  gas  must  be  very  limited." 

Sir  Eobert  Kane  says  of  this  process :  "  After  some  time,  a 
kind  of  mucous  fermentation  sets  in;  carbonic  acid,  ammonia 


INDIGO. 


and  hydrogen  gases  are  evolved,  and  a  yellow  liquor  is  ob- 
tained, which  holds  the  indigo  dissolved.  The  theory  of  this 
action  is,  that  by  the  putrefaction  of  the  vegeto-animal  matter 
of  the  leaves,  the  indigo  is  kept  in  the  same  white  soluble  con- 
dition in  which  it  exists  in  the  plant." 

Dr.  Thomson,  in  his  Vegetable  Chemistry,  supposes  that  the 
indigo  exists  in  the  plant  in  union  with  another  substance,  and 
during  fermentation  that  substance  is  decomposed,  and  carbonic 
acid  gas  consequently  evolved.  But  we  will  give  his.  own 
words  :  "  The  leaves  of  the  indigofera  yield  a  green  infusion  to 
hot  water,  and  a  green  powder  may  be  precipitated  from  it; 
but  unless  a  fermentation  has  taken  place,  neither  the  color 
nor  the  properties  have  any  resemblance  to  those  of  indigo. 
There  is  little  doubt  that  in  the  leaves  it  exists  in  the  state  of 
white  or  deoxygenated  indigo,  and  that  during  the  fermentation, 
it  combines  with  the  requisite  quantity  of  oxygen  to  convert  it 
into  blue  indigo.  The  evolution  of  carbonic  acid  gas  renders  it 
not  unlikely  that  the  white  indigo  was  in  combination  with 
some  principle  (probably  of  an  alkaline  nature)  which  was  de- 
composed during  the  fermentation." 

These  discrepancies  of  opinion  relative  to  the  nature  of  the 
changes  which  take  place  during  fermentation,  show  that  pro- 
per investigations  have  not  yet  been  made  into  this  part  of  the 
process;  and  it  is  obvious  that  until  this  be  done,  any  hypo- 
thesis founded  upon  statements  concerning  the*  gases  evolved, 
must  be  unsatisfactory.  The  supposition  hazarded  by  Dr. 
Thomson  certainly  appears  to  us  the  most  consistent;  for  as 
deoxidized  indigo  combines  readily  with  alkaline  substances, 
and  as  the  vegetable  alkalies  almost  always  contain  nitrogen, 
we  can  easily  conceive  of  that  gas  being  evolved  either  free  or 
in  combination  with  hydrogen,  forming  ammonia.  It  may  yet 
be  found  that  indigo,  like  gallic  acid,  does  not  exist  in  the  liv- 
ing vegetable,  but  is  the  result  of  a  decomposition  of  some 
more  complicated  compound. 

The  chemical  action  wThich  takes  place  in  the  second  vat  in 
which  the  beating  process  is  conducted,  is  apparently  much 
more  easily  explained,  and  therefore  the  discrepancies  among 
writers  on  the  subject  are  not  so  great.  We  shall  give  only- 
two  quotations.  Berthollet  says  :  "  Hitherto,  the  coloring  par- 
ticles have  preserved  their  liquidity.  In  the  second  operation 
the  action  of  the  air  is  brought  into  play,  which,  by  combining 
with  the  coloring  particles,  deprives  them  of  their  solubility, 
and  gives  them  the  blue  color.  The  beating  serves  at  the  same 
time  to  dissipate  the  carboni^  acid  formed  in  the  first  operation, 
which  action  is  an  obstacle  to  the  combination  of  the  oxygen." 
Dr.  Ure's  opinion  is  thus  expressed:    "The  object  of  the 


MANUFACTURE  OF  INDIGO. 


265 


beating  is  threefold  ;  first,  it  tends  to  disengage  a  great  quantity 
of  carbonic  acid  present  in  the  fermented  liquor;  secondly,  to 
give  the  newly-developed  indigo  its  requisite  dose  of  oxygen 
by  the  most  extensive  exposure  of  its  particles  to  the  atmos- 
phere ;  and  thirdly,  to  agglomerate  the  indigo  in  distinct  flocks 
or  granulations.  In  order  to  hasten  the  precipitation,  lime- 
water  is  occasionally  added  to  the  fermented  liquor  in  the 
progress  of  beating;  but  it  is  not  indispensable,  and  has  been 
supposed  to  be  capable  of  deteriorating  the  indigo." 

That  the  liquor  in  the  beating  vat  absorbs  oxygen  from  the 
air,  as  the  indigo  separates  from  it,  has,  we  believe,  been 
ascertained  by  direct  experiment;  and  it  is  also  known  to 
manufacturers,  that  the  sunshine  assists  in  the  separation  of  the 
indigo  from  the  liquor.  But,  though  these  facts  may  have 
been  ascertained,  it  does  not  give  us  any  positive  information 
respecting  the  nature  of  the  change  which  takes  place  in  the 
vat ;  neither  can  we  expect  such  information  till  it  be  ascer- 
tained what  keeps  the  indigo  in  solution  previous  to  the  opera- 
tion of  beating.  Both  oxygenized  and  deoxygenized  indigo 
are  insoluble  in  water  ;  there  must  therefore  be  some  substance 
in  the  liquor  capable  of  holding  the  indigo  in  solution  previous 
to  being  beaten.  According  to  our  present  knowledge  of  the 
nature  of  white  or  deoxidized  indigo,  there  is  no  other  substance 
which  can  hold  it  in  solution  except  the  alkalies  and  alkaline 
earths.  But  during  such  a  generation  and  emission  of  carbonic 
acid  gas,  the  existence  of  any  known  alkali  capable  of  holding 
the  indigo  in  solution  in  those  vats  is  next  to  impossible,  and 
the  results  prove  the  contrary  ;  for  while  the  acid  is  liberated, 
the  indigo  becomes  more  insoluble — a  result  which  is  just  the 
opposite  of  what  we  conceive  would  take  place  were  an  alkali 
present — except  we  suppose  that  the  carbonic  acid  is  the  result 
of  the  decomposition  of  the  alkali,  or  alkaloid,  or  is  evolved 
as  already  hinted,  from  the  decomposition  of  a  substance  which 
is  resolving  itself  into  indigo. 

Having  given  the  opinions  of  several  chemists  upon  the 
chemical  nature  of  the  manufacture  of  indigo,  and  hinted  at 
the  difficulties  which  some  of  these  theories  involve,  we  shall 
now  consider  the  nature  of  indigo ;  and,  whatever  be  the 
chemical  changes  which  take  place  in  the  beating  operation,  we 
are  certain  that  the  indigo  is  precipitated  in  union  with  vari- 
ous other  substances,  rendering  it  very  impure.  The  best  indigo 
of  commerce,  according  to  several  analyses,  contains  only  75 
per  cent,  of  pure  indigo,  while  some  of  the  inferior  kinds  do 
not  contain  above  29  or  30  per  cent.  Part  of  these  impurities 
may  be  dissolved  in  water,  by  alcohol,  by  dilute  acids,  and  by 
alkaline  lyes.    Berzelius  found  those  impurities  to  consist, 


266 


INDIGO. 


besides  a  little  iron,  of  clay,  lime,  magnesia,  and  silica,  of  a 
substance  resembling  vegetable  gluten,*  which  may  be  obtained 
by  digesting  indigo  in  dilute  sulphuric  acid  (vitriol);  also  a 
brown  matter,  which  he  terms  indigo  brown,  and  which  he  ob- 
tained by  digesting  the  indigo  in  strong  potash  lye  after  the 
gluten  had  been  extracted.  He  found  likewise  a  red  resinous 
substance,  which  he  termed  indigo  red;  it  was  obtained  by 
boiling  the  indigo  in  alcohol,  after  digestion  in  the  acid  and 
alkali.  Several  experiments  have  been  made  upon  the  color- 
ing properties  of  these  substances,  but  the  results  have  shown 
that  they  are  incapable  of  being  used  as  a  dye.  On  the  con- 
trary, as  we  shall  afterwards  have  occasion  to  remark,  some  of 
them  being  more  soluble  than  the  pure  indigo,  and  much  more 
easily  decomposed,  their  presence  is  very  hurtful,  especially 
when  the  indigo  is  to  be  used  as  sulphate  of  indigo. 

From  the  great  differences  in  the  quality  of  the  indigo,  it 
would  be  of  the  utmost  importance  to  the  dyer  to  have  an  easy 
method  of  ascertaining  its  true  value.  This,  so  far  as  we  are 
aware,  has  not  yet  been  obtained;  the  various  methods  pro- 
posed generally  imply  formal  analyses,  which,  however  im- 
portant they  may  be  to  the  dyer,  are  too  delicate  and  tedious 
to  be  generally  adopted.  The  method  universally  practised  in 
the  dye-house  is  that  of  comparison— putting  several  samples 
together,  and  breaking  and  comparing  their  clean  surfaces. 
The  best  indigo  generally  is  of  the  deepest  violet  blue,  and  the 
finest  grain,  and  if  scratched  by  the  nail,  it  presents  a  copper 
hue;  but,  notwithstanding  great  care  and  long  practice  in 
judging  of  the  value  of  indigo  in  this  way,  it  often  happens 
that  the  lot -chosen  turns  out  to  be  of  inferior  quality — a  fact 
which  is  not  discovered  until  it  is  in  the  vats. 

The  process  of  Berzelius,  just  alluded  to,  is  to  take  a  weighed 
quantity  of  the  indigo  of  commerce  in  very  fine  powder,  and 
after  digesting  it  in  dilute  sulphuric  acid,  to  filter  and  wash  it ; 
then  digest  what  remains  on  the  filter  in  strong  potash  or  am- 
monia ;  filter  and  wash  again  ;  then  boil  the  remainder  in  strong 
alcohol ;  what  remains  is  pure  indigo,  and,  by  weighing  it,  we 
find  the  percentage  of  real  indigo  in  the  sample. 

Another  process,  somewhat  similar,  was  recommended  by 
Chevreul.  He  treated  the  powdered  indigo  first  with  water, 
then  with  alcohol,  and  afterwards  with  muriatic  acid.  The 
following  is  the  result  of  his  experiment,  taking  a  hundred 
parts : — 

*  Gluten  is  the  substance  which  gives  wheat,  flour,  starch,  &c.  the  pro- 
perty of  paste.  It  is  a  distinct  vegetable  substance,  composed  of  oxygen, 
hydrogen,  nitrogen,  and  carbon,  and  it  is  the  most  nutritive  of  all  vegetable 
compounds. 


TESTING  INDIGO. 


267 


Treated  with 
water. 

Treated  with 
alcohol. 

Treated  with 
muriatic  acid. 

There* 
remained, 


f  Green  matter  united  to  ammonia  "] 
'  A  little  deoxidized  indigo 


Extractive  matter  .... 

Gum   J 

Green  matter  ) 

Eed  resin  I  30 

A  little  indigo  ) 

Eed  resin   6 

Carbonate  of  lime    .....  2 

Eed  oxide  of  iron   2 

Alumina   3 

Silica   3 

Pure  indigo  45 


12  parts. 


103  — 

Although  these  processes  give  a  much  nearer  and  more 
certain  approximation  to  the  true  value  of  indigo  than  the 
mere  comparison  of  samples  by  the  eye,  still  they  are  not 
direct  enough,  and  require  too  much  nice  management  to  be 
resorted  to  generally  in  the  dye-house.  Those,  indeed,  who 
are  most  affected  by  a  bad  bargain,  and  ought  to  be  most  in- 
terested in  any  process  that  would  enable  them  to  avoid  loss, 
and  who  have  the  requisite  time  and  means  to  try  such  experi- 
ments, do  not  seem  impressed  with  the  importance  of  such 
inquiries. 

Another  method  has  been  proposed  by  Dr.  Dana,  of  Lowell, 
United  States,  for  ascertaining  the  real  value  of  commercial 
indigo.  He  directs  that  ten  grains  of  indigo  reduced  to  a  very 
fine  powder,  be  put  into  a  small  glass  flask,  with  two  and  a 
half  ounces,  by  measure,  of  a  solution  of  carbonate  of  soda,  of 
from  30°  to  35°  of  strength  by  Twaddell's  hydrometer ;  after 
boiling  for  a  few  minutes,  8  grains  of  crystals  of  chloride  of  tin 
are  to  be  added,  and  the  whole  boiled  for  half  an  hour.  By 
this  means  the  indigo  is  dissolved,  and  the  liquor  appears  of  a 
yellow  color.  Six  grains  of  bichromate  of  potash  (red  chrome) 
are  dissolved  in  six  ounces  of  water ;  and  when  the  flask  is  with- 
drawn from  the  lamp,  this  solution  of  chrome  is  added,  which 
precipitates  the  indigo  blue,  along  with  a  trace  of  the  indigo 
red,  leaving  the  other  ingredients  in  solution.  The  whole  is 
next  to  be  poured  upon  a  double  (weighed)  filter,  and  the  pre- 
cipitate washed  with  1  ounce  of  muriatic  acid  diluted  with  3 
ounces  of  boiling  water,  and  afterwards  with  hot  water,  till 
nothing  but  water  returns.  Then  separate,  dry,  and  weigh  the 
filters,  and  make  a  note  of  the  weight  of  the  precipitate  ;  burn 
one  filter  paper  against  the  other,  and  their  difference  in  weight 
is  the  quantity  of  silica  contained  in  the  indigo.  This  deducted 


268 


INDIGO. 


from  the  weight  of  the  precipitate,  gives  the  quantity  of  pure 
indigo.  Mr.  Walter  Crum,  who  communicated  the  above  to 
the  British  Association,  in  1841,  added  that  carbonate  of  soda 
with  protoxide  of  tin,  dissolves  indigo,  and  forms  a  yellow 
solution,  but  so  slowly,  that  he  doubts  if  all  the  10  grains  are 
acted  upon.  He  thinks  Dr.  Dana  must  mean  soda-ash,  which 
contains  a  notable  quantity  of  caustic  soda,  but  a  much  weaker 
solution  of  caustic  soda  would  answer  the  purpose. 

Pure  indigo,  besides  its  great  importance  as  a  dye-drug, 
possesses  some  most  important  and  interesting  chemical  pro- 
perties, but  which  are  as  yet  not  very  well  understood.  Some 
of  these  we  shall  notice  before  entering  upon  its  practical 
value.  If  pure  indigo  be  heated  to  about  550°  Fah.,  it  sub- 
limes, producing  a  beautiful  transparent  vapor  of  a  reddish- 
violet  color,  which  adheres  to  the  sides  of  the  vessel  in  which 
it  is  sublimed,  or  on  the  top  of  the  cinder  left,  in  long  needle- 
shaped  crystals.  Mr.  Crum  whose  investigations  have  thrown 
great  light  upon  the  chemical  nature  and  properties  of  indigo, 
employed  for  its  sublimation  the  covers  of  two  platinum  cruci- 
bles, about  three  inches  diameter,  and  of  such  a  form  that, 
when  placed  with  their  concave  sides  inwards,  they  were  about 
three-eighths  of  an  inch  distant  in  the  middle.  About  the 
centre  of  the  lower  lid  were  placed  thinly  about  ten  grains  of 
indigo,  precipitated  from  the  dyer's  vat,  in  small  lumps  about 
a  grain  each;  then,  having  put  on  the  cover,  the  flame  of  a 
spirit  lamp  was  applied  beneath  the  cover  containing  the  indigo. 
The  indigo  immediately  began  to  melt  with  a  hissing  noise, 
which,  when  it  had  nearly  ceased,  the  lamp  was  withdrawn, 
and  the  whole  allowed  to  cool.  On  removing  the  cover,  the 
sublimed  indigo  was  found  planted  on  its  inner  surface  and  a 
little  remained  upon  the  charred  matter,  and  was  easily  re- 
moved. In  this  way  he  obtained  from  18  to  20  per  cent,  of 
the  indigo  employed.* 

As  few  workingmen  have  access  to  platinum  crucible  covers 
to  repeat  this  experiment,  we  may  state,  that  it  may  be  suc- 
cessfully repeated  by  taking  a  thin  porcelain  plate,  or  a  sheet 
of  iron  or  copper,  with  the  indigo  placed  upon  it,  and  covering 
it  with  a  pretty  large  watch-glass ;  when  the  plate  under  the 
indigo  is  heated  by  a  lamp,  the  vapors  very  soon  make  their 
appearance;  and,  towards  the  close,  the  glass  appears  black, 
owing  to  the  coating  of  indigo  which  adheres  to  its  inner 
surface.  To  obtain  pure  indigo  for  this  experiment,  the  easiest 
method  is  to  take  a  little  of  the  yellow  solution  of  the  indigo 
vat.    On  adding  to  this  a  few  drops  of  muriatic  acid,  to  dis- 


*  Annals  of  Philosophy  for  January,  1823. 


TESTING  INDIGO. 


269 


solve  the  salts  of  lime,  the  blue  indigo  falls  to  the  bottom, 
and  may  readily  be  collected  upon  a  filter,  then  washed  and 
dried. 

Another  method  has  been  described  by  T.  Taylor,  Esq., 
which  is  as  follows:  "Any  quantity  of  indigo  is  to  be  reduced 
to  powder,  and  mixed  with  about  half  its  weight  of  plaster  of 
Paris.  To  these  materials,  so  much  water  is  to  be  added  as 
will  bring  the  whole  to  a  thin  paste.  This  is  to  be  spread 
evenly  upon  an  iron  plate  to  the  depth  of  the  eighth  of  an 
inch,  and  allowed  to  remain  exposed  to  the  air,  or  to  a  gentle 
heat,  until  it  is  tolerably  dry.  If  the  heat  of  a  large  spirit- 
lamp  'be  now  applied  to  the  under  surface  of  the  plate,  the 
indigo  begins  to  smoke,  emits  a  disgusting  odor,  and  in  a  few 
minutes  is  covered  over  with  a  dense  purple-red  vapor,  which 
condenses  into  brilliant  flattened  prisms,  or  plates  of  an  intense 
copper  color,  forming  a  thick  velvety  coating  over  the  surface- 
immediately  exposed  to  heat.  When  this  ceases  to  appear,  the 
heat  is  of  course  to  be  withdrawn  ;■  and  when  cold  the  sub- 
limed crystals  may  be  readily  lifted  or  swept  off,  without  in 
the  slightest  disturbing  the  subjacent  mass.  The  operation  is 
exceedingly  beautiful  to  look  at,  is  effected  in  a  few  minutes, 
and  any  quantity  of  materials  might  be  acted  upon.  For 
ultimate  analysis,  the  sublimed  indigo  must  be  previously 
washed  with  alcohol  or  ether.  The  object  of  the  plaster  is  to 
prevent  the  indigo  from  cracking  during  drying.* 

We  have  tried  this  experiment  repeatedly,  but  the  results 
did  not  promise  favorably  for  the  process  being  of  practical 
value  in  the  dye-house. 

Another  method,  and  of  much  easier  practice  in  the  dye- 
house  than  any  of  those  given,  is  by  Henry  Schlumberger  :— 

"  This  test  consists  in  dissolving  the  indigo  in  fuming  sul- 
phuric acid,  and  decolorizing  the  solution,  which  has  been 
diluted  with  much  water,  by  means  of  chloride  of  lime.  As 
this  acts  only  on  the  blue  coloring  substance,  and  not  at  the 
same  time  on  the  various  other  bodies  which  indigo  contains, 
the  quantity  of  chloride  of  lime  requisite  to  produce  decoloriza- 
tion  agrees,  as  will  be  subsequently  seen,  accurately  with  the 
amount  of  coloring  matter. 

"  The  operations  in  this  experiment  are  as  follows:  I  pre- 
pare, in  the  first  place,  a  portion  of  pure  indigo  or  indigo  blue 
by  removing  the  scum  which  is  continually  formed  on  the  blue 
vat,  treating  it  with  an  excess  of  dilute  hydrochloric  acid, 
washing  the  deposit  until  all  soluble  parts  have  been  removed, 
then  drying  it  and  preserving  the  indigo  in  well-closed  bottles, 


*  Chemical  Gazette,  vol.  i.  page  115. 


270 


INDIGO. 


in  order  to  protect  it  from  all  changes  in  the  moist  state:  In 
all  my  experiments  this  pure  indigo  serves  as  a  standard,  and 
for  comparison  with  the  results  which  the  various  kinds  of  in- 
digo submitted  to  the  test  afford.  Suppose  the  quantity  of 
coloring  matter  in  the  purfe  indigo  to  be  100°,  I  express  the 
value  of  the  tested  indigo  by  numbers  which  indicate  the  per- 
centage of  pure  coloring  matter.  In  each  experiment  I  employ 
the  standard  indigo  for  comparison  with  that  of  commerce,  as 
it  is  then  not  requisite  to  determine  previously  the  amount  of 
chloride  of  lime  in  solution  ;  besides  which,  the  experiment  is 
more  accurate.  In  this  case  the  causes  of  the  differences  in  the 
results  depend  on  circumstances,  which  always  remain  the  same 
whether  the  standard  indigo  is  employed,  or  the  indigo  the 
degree  of  purity  of  which  is  to  be  ascertained.  Twenty  grains 
of  each  kind  of  indigo  are  weighed  off,  which  must  be  pulver- 
ized and  finely  ground  ;  half  an  ounce  of  fuming  sulphuric  acid 
is  added,  and  the  mixture  is  now  rubbed  together,  the  dish 
containing  it  being  placed  for  four  hours  at  a  temperature  of 
from  122°  to  140°. 

"  Meantime  as  many  glasses,  containing  about  a  quart,  are 
filled  with  distilled  water  as  there  are  sulphate  solutions,  and 
to  each  solution  of  indigo  is  added  its  equal  volume  of  water 
from  the  glass.  The  liquid  becomes  warm,  upon  which  they 
are  rubbed  again  ;  water  is  then  gradually  added  until  the  dish 
is  full,  when  the  whole  is  poured  into  the  glass,  and  the  dish 
washed  with  a  portion  of  the  water.  Hereupon  a  solution  of 
chloride  of  lime  is  prepared  of  2°  Twad.  in  strength,  and  a  given 
quantity  taken,  say  10  graduations  of  an  alkalimeter. 

u  The  well-stirred  blue  solution  of  the  sulphate  of  indigo  is 
now  measured  in  an  alkalimeter,  a  tube  divided  into  100°,  and 
a  portion  poured  into  a  dish,  well  stirred,  and  the  entire  quan- 
tity of  the  chloride  of  lime  contained  -  in  the  measure  added  at 
once.  If  the  liquid  immediately  assumes  a  yellow  color,  it  is 
a  sign  of  an  excess  of  chloride  of  lime,  and  now  sulphate  of 
indigo  is  added  by  degrees  until  a  faint  olive-green  coloring 
has  been  obtained.  The  experiment  is  now  repeated,  and  the 
quantity  of  chloride  of  lime  which  had  been  found  necessary 
in  the  first  case  added  to  the  quantity  of  sulphate  of  indigo;  so 
that  with  one  single  mixing,  there  being  neither  an  excess  of 
chloride  of  lime  nor  of  sulphate  of  indigo,  the  liquid  acquires 
that  tint  at  once.  But  when,  after  the  first  mixture,  the  liquid 
has  retained  a  blue  color,  which  is  a  sign  of  an  excess  of  the 
sulphate  of  indigo,  fewer  degrees  of  it  are  taken  until  the  requi- 
site tint  has  likewise  been  attained  with  a  single  mixing. 

"  When  the  several  indigoes  have  been  treated  in  this  man- 
ner, the  following  calculation  is  made  to  obtain  the  true  value 


TESTING  INDIGO. 


271 


of  the  indigo  which  has  been  examined ;  the  goodness  of  the 
indigo  is  in  inverse  ratio  to  the  quantity  of  sulphate  of  indigo 
employed  in  decolorizing. 

"  Suppose,  for  instance,  it  were  found  that  pure  indigo  re- 
quired 54  parts  of  its  sulphate  solution  to  be  decolorized  by 
the  fixed  quantity  of  chloride  of  lime,  and  that,  on  the  other 
hand,  the  indigo  under  examination  required  64  parts  of  its 
sulphate  solution,  then  according  to  the  proportion — 

100x54 

64  :  54=100  :  cc,  =cc,  or  equal  to  84.5,  which 

64 

indicates  the  quantity  of  indigo  blue  contained  in  100  parts  of 
the  ftidigo  examined. 

"  It  is  important  for  the  accuracy  of  the  experiment  that  the 
pure  indigo,  and  the  kinds  of  indigo  submitted  to  the  test, 
should  be  equally  moist,  and  it  is  therefore  requisite  to  inclose 
all  the  samples  as  soon  as  they  are  taken  out  of  the  chests  in 
glass  phials,  to  prevent  any  attraction  of  moisture  or  desiccation 
previous  to  weighing.  When  a  chest  contains  several  kinds 
of  indigo  which  exhibit  slight  differences  in  their  tints,  some 
pieces  are  selected  which  are  separated  into  several  lots ;  these 
are  then  powdered  together,  and  the  mean  result  taken  as  the 
correct  one.  But  when,  as  often  happens,  a  chest  contains 
pieces  of  indigo  of  entirely  different  tints,  it  is  best  to  examine 
the  mixed  sorts  separately. 

"I  also  dilute  the  solution  both  of  the  sulphate  of  indigo 
and  of  that  of  the  chloride  of  lime,  since  the  experiment  in  this 
manner  is  less  exposed  to  error  than  with  concentrated  solutions. 
Besides,  it  is  easier  when  the  liquid  is  only  faint  blue  to  distin- 
guish the  degree  of  decolorization,  when  it  must  be  discontinued. 

"  Impure  water,  or  such  as  contains  salts  of  lime,  produces 
a  more  or  less  considerable  precipitate  of  the  blue-coloring  sub- 
stance mixed  with  sulphate  of  indigo  ;  it  is  therefore  necessary 
to  employ  rain  or  distilled  water. 

u  The  last  stage  of  decolorization,  or  the  point  at  which  it  is 
best  to  discontinue  it,  is  the  more  easily  ascertained,  the  purer 
the  indigo,  and  the  more  complete  its  solution  ;  and  in  this 
case  it  is  evident  how  sensitive  the  reaction  of  the  chloride  of 
lime  is  on  the  indigo;  for  a  yellow  solution  of  indigo,  to  which 
chloride  of  lime  has  been  added,  in  which,  therefore,  there  is 
an  excess  of  chloride  of  lime,  is  rendered  blue  by  a  single 
degree  of  the  indigo  solution,  a  proof  that  this  method  will 
indicate  a  half  per  cent.  In  the  commercial  kinds  of  indigo  it 
is  less  easy  to  fix  the  point  at  which  decolorization  must  be 
discontinued,  for  in  this  case  the  decolorized  liquid  assumes  an 


272 


INDIGO. 


olive  color,  and  from  2°  to  3°  of  the  indigo  solution  must  be 
added  to  change  the  yellow  color  into  the  blue. 

"I  have  preferred  the  method  of  taking  a  fixed  quantity  of 
the  chloride  of  lime  and  varying  that  of  the  sulphate  of  indigo, 
to  that  of  making  the  sulphate  of  indigo  a  fixed  quantity,  and 
allowing  the  decolorizing  agent  to  be  diminished  or  increased, 
from  its  being  possible  to  dilute  the  indigo  solution  with  much 
water,  which  has  the  advantage  of  rendering  the  degrees 
greater." 

Another  method,  and  of  much  easier  practice  in  the  dye- 
house,  is  thus  given  by  M.  Reinsh  : — 

Reinsh  tried  various  modes  of  determining  the  goodness  of 
indigo — such  as  the  external  appearance ;  the  intensity  of 
color  imparted  to  yarn  by  the  cold  vat;  the  quantity  of  ifdigo 
blue  obtained  by  sublimation;  the  quantity  of  indigo  blue 
deposited  from  the  cold  vat ;  and  the  specific  weight.  Not  one 
of  these  methods,  however,  gave  results  to  be  relied  on. 

"At  last,"  he  says,  "I  resorted  to  fuming  sulphuric  acid, 
and  obtained  the  most  satisfactory  results.  It  is  necessary, 
however,  that  the  indigo  should  be  pounded  very  fine,  and  the 
acid  should  be  as  concentrated  as  possible.  I  must  also 
observe,  that  the  solution  of  the  Java  indigo,  and  of  that  indigo 
which  I  prepared  in  a  chemical  way,  by  treating  it  with  acid, 
caustic  potash,  spirit  of  wine  and  water,  did  not  possess  the 
pure  blue  color  like  that  of  the  Bengal  sort,  although  I  repeated 
the  experiments  several  times,  and  could  not,  therefore,  deter- 
mine anything  with  regard  to  the  purified  indigo.  A  dyer  of 
great  experience  informed  me,  that  for  solution  in  sulphuric 
acid  he  prefers  Bengal  to  the  Java  sort,  as  the  latter  is  burnt 
by  the  acid,  which  is  always  the  case  when  the  indigo  does  not 
dissolve  with  a  pure  blue  color,  but  assumes  a  crimson  hue  on 
the  sulphuric  solution  being  poured  in  water. 

"  The  mode  in  which  I  proceed  is  as  follows  :  2  grains  of  each 
sample  of  indigo  are  well  pounded,  mixed  with  four  or  five 
drops  of  fuming  sulphuric  acid,  and  rubbed  with  it  until  the 
whole  forms  a  brown  uniform  mass.  To  this,  15  grains  of 
sulphuric  acid  are  added,  and  triturated  till  it  produces  a  clear 
green  solution,  whereupon  other  15  grains  of  fuming  sulphuric 
acid  are  added;  lastly,  this  solution  is  gradually  mixed  with 
150  grains  of  water.  Two  glass  cylinders  of  equal  length  and 
width  are  now  divided  each  into  twenty  equal  parts,  and  15 
grains  of  the  sulphuric  solution  (which  is  best  measured  by  a 
glass  tube  closed  at  one  end)  poured  into  one  and  mixed  with 
water,  till  the  solution  is  of  a  light-blue  color  and  transparent  ; 
if  15  grains  of  the  solution  do  not  produce  sufficient  coloriza- 
tion,  a  small  quantity  more  of  it  is  added,  till  the  cylinder  is 


TESTING  INDIGO.  273 

filled  with  the  light-blue  solution.  I  generally  commence  with 
the  apparently  best  indigo.  After  this,  the  second  cylinder  is 
filled  in  the  same  way  with  an  equal  quantity  of  sulphuric 
solution  of  the  same  indigo  sample  and  water,  in  order  to  see 
whether  the  two  solutions  are  equal  in  color.  If  this  be  the 
case,  one  of  the  cylinders  is  emptied,  and  an  equal  quantity  of 
sulphuric  solution  of  an  inferior  sample  poured  into  it  and 
gradually  diluted  with  water,  till  the  solutions  in  both  cylinders 
are  perfectly  alike  in  color.  Care  is  to  be  taken  that  the 
coloration  be  not  too  intense  nor  too  light,  it  being  in  either 
case  difficult  to  obtain  both  solutions  of  the  same  hue.  For 
discovering  this  equality  the  eye  will  also  be  much  assisted  if 
the  relative  position  of  the  cylinders  is  changed  from  the  right 
to  the  left,  or  by  placing  them  alternately  before  or  behind  one 
another.  As  soon  as  the  color  of  both  is  thus  found  to  be 
equal,  the  quantity  of  water  is  examined  which  has  been  poured 
into  the  second  cylinder.  Supposing  now  that  15  grains  of 
sulphuric  solution  have  been  employed  in  either  of  the  cylinders, 
but  the  quantity  of  water  which  produced  the  equal  color  was 
in  the  first  or  standard  cylinder  20  parts,  and  in  the  second 
only  15  parts,  then  the  sample  of  which  the  latter  solution  was 
made  will  contain  25o^ns?  or  one  quarter  less  of  coloring  matter. 

"This  method  is  so  easy  and  convenient  that  everybody  can 
avail  himself  of  it.  All  that  is  required  is  to  keep  ready 
a  certain  quantity  of  indigo  solution  of  a  known  quality  as 
standard  solution,  and  then  to  prepare  a  sulphuric  solution  of 
the  indigo  to  be  tested. 

uThe  above-described  method  may  even  be  made  more 
accurate,  if  longer  glass  cylinders  are  used,  so  that  the  per- 
centage quantities  may  be  indicated.  The  glasses  must  then 
be  divided  in  100  parts.  The  larger  the  degrees  are,  the  more 
accurate  will  the  results  be. 

"I  have  yet  to  add  some  observations  with  regard  to  an 
adulteration  practised  on  the  indigo,  and  which  is  of  import- 
ance to  the  druggist.  Each  large  indigo-chest  contains  a 
quantity  of  dust,  which  is  said  to  amount  sometimes  to  eight 
or  ten  pounds.  This  dust  is  an  artificial  product,  composed  of 
starch  or  white  lead  and  powdered  indigo,  and  is  put  in  the 
chest  in  order  to  increase  its  weight." 

Another  process  of  testing  the  value  of  indigo  has  been  re- 
commended by  Dr.  Bolley,  depending  also  upon  the  decoloriz- 
ing by  chlorine,  by  a  method  which  insures  the  constancy  of  the 
chlorine;  this  is  done  by  using  hydrochloric  acid  and  chlorate 
of  potash.  A  given  quantity  of  indigo,  say  100  grains,  is 
ground  into  powder,  and  converted  into  sulphate  of  indigo  by 
adding  to  the  100  grains  about  2J  ounces  of  the  strongest  sul- 
18 


274 


INDIGO. 


phuric  acid,  and  allowing  it  to  stand  for  six  or  eight  hours. 
The  whole  is  now  put  into  an  evaporating  basin  or  flask,  with 
about  one  pint  of  water,  and  one  quarter  of  an  ounce,  by  mea- 
sure, of  hydrochloric  acid,  and  brought  to  boil.  A  solution  of 
chlorate  of  potash  is  now  made  in  100  measures  of  water  by 
alkalimeter  (which  is  added  to  the  indigo  solution),  the  blue 
liquor  passes  into  green,  brownish-green,  and  lastly  into  red, 
when  the  operation  is  finished.  A  little  experience  will  show 
the  exact  time  to  stop.  The  amount  of  chlorate  solution  taken 
to  effect  this  is  noted,  and  a  standard  solution  being  made,  the 
relative  value  of  indigo  will  be  easily  ascertained. 

Another  method  of  testing  the  value  of  indigo  has  been  re- 
cently recommended  by  Dr.  Penney,  of  the  Andersonian  Univer- 
sity, Glasgow,  based  upon  the  circumstance  that  indigo  blue, 
in  presence  of  hydrochloric  acid,  is  decolorized  by  bichromate 
of  potash.  Ten  grains  of  the  sample,  in  very  fine  powder,  are 
dissolved  in  2  drachms,  by  measure,  of  fuming  sulphuric  acid, 
forming  sulphate  of  indigo.  After  standing  several  hours,  to 
insure  complete  solution,  it  is  diluted  with  a  pint  of  water,  and 
the  whole  well  stirred,  after  which  there  is  added  f  of  a  volume 
ounce  of  hydrochloric  acid.  Seven  and  a  half  grains  of  dry 
and  pure  bichromate  of  potash  are  now  dissolved  in  water — 
the  whole  solution  to  be  equal  to  100  measures  of  an  alkalime- 
ter; this  is  added  drop  by  drop  to  the  sulphate  of  indigo,  until 
the  blue  color  disappears,  and  the  color  of  a  drop  of  the  solu- 
tion put  on  a  white  plate  or  paper  be  orange-brown,  having  no 
green  or  blue  tint.  The  number  of  graduations  required  to 
effect  this  is  noted.  Dr.  Penney  found  that  7|  grains  bichro- 
mate of  potash  were  equal  to  10  grains  pure  indigo,  so  that 
every  ten  graduations  of  the  solution  taken  to  decolor  the  sul- 
phate, are  equal  to  one  grain  of  pure  indigo,  or  one  graduation 
to  a  per  cent,  of  indigo. 

Commercial  Indigoes. — The  following  description  of  com- 
mercial indigoes  is  taken  from  Dumas'  Lectures  upon  Agricul- 
culture : — 

"  Indigoes  of  Commerce. — The  indigoes  of  commerce  have 
been  described  in  a  very  able  manner  by  M.  Chevreul.  The 
following  details  are  extracted  from  his  work:  They  are  some- 
times in  small,  light  pieces,  of  a  violet-brown  color,  and  some- 
times in  cubical  loaves.  These  loaves  may  be  considered  good, 
when  they  assume  a  copper-colored  aspect  on  friction  with  any 
hard  and  smooth  body — when  there  are  no  cavities  found  in 
their  interior,  presenting  a  series  of  brown  or  whitish-colored 
streaks — and,  lastly,  when  they  are  free  from  fissures  externally. 
If  they  are  of  a  blue  instead  of  a  violet  color,  it  is  a  proof 
that  they  contain  more  or  less  of  the  yellow  matter.  The 


COMMERCIAL  INDIGOES. 


275 


presence  of  this  matter  in  large  proportions,  tends  by  its  ad- 
mixture to  convert  the  blue  into  a  green,  and  also  neutralizes 
the  color  of  the  red  matter  of  indigo.  An  obscure  dark-brown 
or  dirty-green  color  indicates,  in  general,  that  the  indigoes  have 
undergone  some  deterioration  in  their  preparation  or  during 
their  transport.  Indigo  is  destitute  of  odor,  provided  it  has 
undergone  no  alteration  by  heat  and  moisture.  Indigoes  are 
classified  into  different  kinds,  according  to  the  country  in  which 
they  are  prepared,  or  according  to  their  color. 

"  First,  Indigoes  prepared  in  Asia — they  are  from  Bengal, 
Coromandel,  Madras,  Manilla,  and  Java: — 

"  Bengal  Indigoes. — The  trade  in  this  indigo  is  chiefly  carried 
on  in  Calcutta,  and  through  the  medium  of  the  East  India 
Company;  its  varieties  are  very  .-numerous.  The  principal, 
commencing  with  those  of  the  best  quality,  are:  1°  The  super- 
fine or  light  blue.  This  is  im  a  cubical  form,  light  and  friable, 
soft  to  the  touch,  of  a  clean  fracture,  and  giving  a  beautiful 
copper  color  on  being  rubbed  with  the  nail.  2°  Superfine 
violet.  3°  Superfine  purple.  4°  Fine  violet,  in  color  a  little 
less  brilliant  than  the  superfine,  and  rather  heavier.  5°  Fine 
purple  violet.  6°  Good  violet,  somewhat  heavier  than  the  fine 
violet.  7°  Violet  red.  8°  Common  violet.  9°  Fine  and  good 
red,  heavier  than  the  preceding,  color  bordering  decidedly  on 
red.  10°  Good  red,  of  a  firmer  and  more  compact  structure. 
11°  Fine  copper-colored,  redder  and  more  compact  still.  12° 
Middling  copper-colored.  13°  Ordinary  and  low  copper- 
colored  ;  this  is  of  a  copper-colored  blue  or  red,  somewhat  diffi- 
cult to  break. 

"  Coromandel. — Those  of  the  best  quality  correspond  to  the 
middling  Bengal  indigoes,  and  are  met  with  in  square  masses, 
having  an  even  fracture,  but  are  more  difficult  to  break.  The 
inferior  indigoes  are  heavy,  of  a  sandy  feel,  having  a  blue  color 
bordering  on  green  or  gray,  or  even  black  ;  often  in  very  large 
squares,  and  covered  with  a  slight  crust  or  rind  of  a  greenish- 
gray  color.  These  are  the  most  difficult  to  break  of  all  the 
indigoes  of  commerce. 

"Madras. — They  have  a  grained  rough  fracture,  and  are  of  a 
cubical  figure.  The  superior  qualities  have  no  rind ;  in  figure 
they  somewhat  resemble  a  hat,  and  are  more  light  and  friable 
than  those  of  Coromandel.  These  indigoes,  when  of  the  best 
quality,  have  great  lightness,  but  are  not  equal  to  the  superfine 
blue  of  Bengal.  The  middling  qualities  have  a  very  slight 
copper-color.  The  color  of  the  inferior  qualities  is  a  dark  or 
muddy  blue,  black,  or  even  gray,  and  greenish. 

64  Manilla. — These  present  the  mark  of  the  rushes  upon  which 
they  have  been  dried.    They  are  of  a  finer  consistence  and 


276 


INDIGO. 


lighter  color  than  are  the  indigoes  of  Madras,  but  not  so  fine 
as  the  indigoes  of  Bengal.  The  better  qualities  are  often  in  flat 
and  elongated  masses,  somewhat  porous,  and  consequently  light. 
The  middling  qualities  are  of  a  violet  color,  but  they  are  infe- 
rior to  the  violet  of  Bengal. 

"  Java. — In  flat,  square  masses,  sometimes  of  a  lozenge  shape. 
The  superior  qualities  appear  to  the  sight  as  fine  as  the  blue, 
violet,  or  red  indigoes  of  Bengal ;  but  they  are  not  so  in 
reality. 

"  Second,  Indigoes  prepared  in  Africa.  They  are  from 
Egypt  and  Senegal : — ■ 

"  Egypt. — The  superior  qualities  of  Egyptian  indigo  are  su- 
perfine and  fine  violet  blues.  They  are  light,  but  their  struc- 
ture is  not  very  fine,  and  they  often  contain  sand.  The  squares 
are  rather  flatter  than  those  of  Bengal. 

"  Senegal. — They  are  of  good  quality,  but  they  contain  more 
earthy  matter  than  any  other  indigoes  in  the  trade. 

"  Third,  Indigoes  from  America ;  those  of  Guatimala,  Carac- 
cas,  Mexico,  Brazil,  Carolina,  and  the  Antilles: — 

"  The  indigoes  of  Guatimala,  of  the  Garaccas,  and  of  Mexico, 
are  of  various  kinds.  The  best  are  of  a  bright  blue  color, 
remarkably  light  and  fine.  These  indigoes  are  esteemed  equal 
to  the  best  Bengal.  The  inferior  qualities  are  of  a  violet  color, 
but,  in  general,  are  more  mixed  than  the  Bengal  kinds. 

"  Brazil. — These  indigoes  are  in  small  rectangular  parallel- 
opiped  masses,  or  in  irregular  lumps,  of  a  greenish-gray  color 
externally,  and  having  a  smooth  fracture,  a  firm  consistence, 
and  a  copper-colored  tint  of  greater  or  less  brilliancy. 

"  Carolina. — In  small  square  masses,  having  a  gray  exterior. 
The  best  qualities  have  a  dull  copper  color,  bordering  on  violet 
or  blue.  The  common  qualities  are  almost  always  of  a  green- 
ish-blue ;  they  are  rarely  found  of  a  copper  color. 

"The  principal  varieties  of  indigo  in  commerce  are  the 
Bengal,  the  Caraccas,  the  Guatimala,  the  Madras,  and  the 
Manilla. 

"Besides  the  numerous  shades  already  described,  we  should 
also  be  on  our  guard  against  certain  defects  of  greater  or  less 
consequence,  and  which  depend  on  causes  acting  either  on  the 
indigo  when  already  prepared,  or  else  occurring  during  its 
preparation.  The  following  are  some  of  the  characters  to  be 
borne  in  mind  :  The  large  or  small  fracture  ;  squares  of  indigo 
reduced,  by  accident,  into  lumps  of  variable  size.  Fragments: 
squares  reduced  into  irregular  pieces,  and  fine  enough  to  be 
passed  through  a  sieve.  Sometimes,  also,  we  meet  with  squares 
which  are  readily  broken,  and  which  present  a  whitish  kind  of 
mouldiness  in  their  interior.    Gritty  lumps,  throughout  which 


CHARACTERISTICS  OF  INDIGO. 


277 


are  points  presenting  the  appearance  of  granite.  Streaky 
masses,  in  which  are  layers  of  various  shades  of  blue,  placed 
one  above  the  other,  in  the  same  square.  Pieces  of  a  scorched 
appearance,  which,  on  being  sharply  rubbed  between  the 
hands,  are  ground  into  small  fragments,  nearly  black  in  color. 
Sandy  lumps,  in  the  interior  of  which  the  eye  can  detect 
shining  specks,  which  are  nothing  more  than  sand." 

Pure  indigo,  whether  obtained  by  sublimation  or  other 
chemical  means,  is  of  a  deep  blue  approaching  to  violet.  If 
scratched  or  rubbed,  it  has  a  strong  copper  hue,  and  a  metallic 
lustre.  It  has  neither  taste  nor  smell,  and  is  remarkable  for 
its  neutral  properties.  It  is  insoluble  in  water,  alcohol,  ether, 
alkalies,  and  dilute  acids.  Strong  sulphuric  acid  dissolves 
indigo  readily,  and  forms  with  it  a  purple-blue  solution.  Its 
chemical  composition  is,  according  to  Mr.  Crum  and  M. 
Da  mas : — 


16  Carbon. 
5  Hydrogen. 
2  Oxygen. 
1  Nitrogen. 


or  double, 


r 


32  Carbon. 
10  Hydrogen. 

4  Oxygen. 

2  Nitrogen. 


The  double  proportion  is  preferred,  as  it  agrees  better  with 
some  of  the  reactions  to  be  hereafter  explained. 

The  chemical  qualities,  and  some  of  its  reactions  have  been 
extensively  studied.  If  blue  indigo  be  brought  into  contact 
with  substances  having  a  strong  attraction  for  oxygen  in  the 
presence  of  an  alkali,  the  indigo  is  reduced  to  the  white  state, 
and  becomes  soluble  in  the  alkali ;  this,  as  is  well  known,  is 
the  principle  of  the  blue  vat.  The  following  matters  all  reduce 
blue  indigo  to  whiter- 


Protoxide  of  tin, 
Protoxide  of  iron, 
Sulphuret  of  arsenic, 
Phosphorus, 
The  phosphites, 
Sulphites, 


The  sulphurets  of  potassium, 

Sodium, 

Calcium, 

Sugar, 

Starch, 

Tannin. 


Salts  which  yield  oxygen,  as  those  of  copper,  turn  white 
indigo  to  blue,  and  the  copper  is  reduced  to  the  suboxide. 
Water  having  carbonic  acid,  also  oxidizes  white  indigo.  In- 
digo white  is  a  crystalline  solid,  having  a  fibrous  silky  lustre, 
tasteless,  without  smell,  and  heavier  than  water;  it  is  insoluble 
in  water,  but  soluble  in  alcohol  and  ether. 

White  indigo,  well  dried,  may  be  kept  in  the  air  for  several 
days  without  change,  but  if  moist  it  soon  becomes  blue ;  when 
heated  it  becomes  purplish-blue.    The  composition  of  white 


278 


INDIGO. 


indigo  is  still,  to  some  extent,  an  unsettled  question.  According 
to  the  most  generally  received  opinion,  white  indigo  is  blue 
indigo  with  less  oxygen,  sometimes  called  deoxidized  indigo, 
but  Dumas  considers  it  as  blue  indigo,  with  an  equivalent  more 
of  hydrogen  ;  thus  we  have 

By  the  Common  Theory.  By  Dumas 's  Theory. 

Carbon  16  Carbon  16 

Nitrogen  1  Nitrogen  1 

Hydrogen  5  Hydrogen  6 

Oxygen  2  Oxygen  2 

Dumas  supports  his  view  of  the  matter  by  reference  to 
many  vegetable  organic  substances  which  he  thinks  comport 
themselves  in  a  similar  manner,  and  gives  a  series  of  formulae 
of  compounds,  which  by  analogy  he  connects  with  indigo. 
Thus:— 


c. 

H. 

0. 

H. 

N. 

Blue  indigo  (double  atom)  . 

32 

10 

2 

0 

2 

"White  indigo      .  . 

32 

10 

2 

2 

2 

Acetyle  .... 

8 

6 

2 

0 

0 

Aldehyde  .... 

8 

6 

2 

2 

0 

Benzole  .... 

28 

10 

2 

0 

0 

Oil  of  bitter  almonds  . 

28 

12 

2 

2 

0 

Cinnamole  .... 

36 

14 

2 

0 

0 

Oil  of  cassia 

36 

14 

2 

2 

0 

Here  we  observe  a  series  of  compounds  differing  more  widely 
from  each  other  than  white  and  blue  indigo,  and  only  caused 
by  having  two  proportions  more  of  hydrogen.  A  like  analogy 
is  carried  out  between  compounds  of  indigo  with  other  bodies, 
and  compounds  of  other  organic  substances,  which,  however, 
we  must  pass  over. 

Liebig's  view  of  the  reaction  of  indigo,  and  its  relations  to 
other  bodies,  differs  from  that  of  Dumas.  He  considers,  as 
the  result  of  careful  and  extensive  investigation,  that  indigo 
contains  a  salt  radical  (page  45)  which  he  terms  anyle ,  and 
which  is  composed  of  C16H5N.  This,  it  will  be  observed,  is 
indigo  without  any  oxygen.  He  then  considers  that  white 
indigo  is  the  hydrated  protoxide  of  this  base  or  radical,  and 
that  blue  indigo  is  the  peroxide.    Thus: — 

C.       H.    ST.    0.  Water. 

Anyle   16  5  1  0  0 

White  indigo      .              .  16  5  1  1  1 

Blue  indigo.       .       .       .  16  5  1  2  0 
Taking  double  proportions  for  comparison: — 

Anyle   32  10  2  0  0 

White  indigo      .       .       .  32  10  2  2  2 

Blue  indigo.       .       .       .  32  10  2  4  0 


INDIGO.  279 

This  view  of  the  matter,  which  we  think  most  consistent 
with  fact,  and  to  which  we  may  have  occasion  to  return  in 
describing  the  vat,  can  be  supported  by  analogies  in  the  same 
manner  as  the  other  view.  Indeed,  most  of  the  coloring  prin- 
ciples of  vegetables,  such  as  madder,  annotta,  archil,  &c,  exist 
in  the  plants  as  colorless  bases,  and  become  colored  by  the 
absorption  of  oxygen. 

M.  Pressier,  who  has  been  very  fortunate  in  his  researches 
into  vegetable  coloring  matters  and  bases,  thinks  that  he  has 
found  a  decisive  argument  in  favor  of  Liebig's  view,  in  the 
fact  that  blue  indigo,  sugar,  and  potash  react  together,  and 
form  white  indigo.  He  therefore  considers  it  very  improbable 
that  indigo  should  extract  hydrogen  from  water,  at  the  same 
time  that  the  oxygen  of  the  water  would  combine  with  the 
hydrogen  of  the  sugar  to  reproduce  water.  Dumas,  however, 
observed  upon  this,  that  there  is  no  necessity  for  supposing 
water  to  be  decomposed,  as  the  hydrogen  of  the  sugar  may 
combine  directly  with  the  indigo  blue  and  form  indigo  white. 
These  views  of  the  question  show  that  the  subject  is  still  one 
of  difficulty,  and  is  full  of  interest;  and  that  the  daily  expe- 
rience of  the  dyer,  were  the  results  carefully  observed,  might 
afford  important  aid  towards  the  solution  of  some  of  those 
vexed  questions  of  chemical  science. 

If  indigo  be  thrown  into  fused  hydrate  of  potash,  its  blue 
color  disappears;  it  dissolves,  and  is  partly  decomposed  along 
with  the  water  of  the  alkaline  hydrate;  hydrogen  and  ammo- 
niacal  gases  are  evolved,  while  carbonic  acid,  and  another  acid,, 
named  valerianic  acid,  having  properties  similar  to  acetic  acid, 
are  formed,  and  combine  with  the  potash.  By  digesting  this 
mixture  with  a  little  sulphuric  acid,  the  alkali  combines  with 
it,  and  the  new  acid  crystallizes.  This  acid  combines  with 
alkalies  and  other  bases,  and  forms  a  very  interesting  series  of 
salts. 

If  indigo,  in  fine  powder,  be  added  to  nitric  acid,  diluted 
with  seven  or  eight  times  its  weight  of  water,  and  a  gentle 
heat  be  applied,  it  dissolves  with  effervescence,  forming  a  yel- 
low liquid.  After  standing  a  little,  this  liquid  may  be  decanted 
from  any  resinous  matter  formed  during  the  process,  and  con- 
centrated by  evaporation,  and  speedily  there  will  be  found 
deposited  a  quantity  of  yellowish- white  crystals,  having  a 
sourish-bitter  taste,  and  requiring  about  100  parts  of  cold 
water  for  their  solution.  This  was  formerly  termed  indigotic 
acid,  but  is  now  called  anilic  acid,  from  the  species  and  name 
of  one  of  the  plants  which  yield  indigo.  It  combines  with  all 
known  bases,  forming  salts,  which  have  generally  a  yellow 


280 


INDIGO. 


color.  It  gives  a  blood-red  color  to  solutions  of  the  persalts 
of  iron. 

If  indigo  be  added  to  strong  nitric  acid,  and  heat  be  applied, 
it  quickly  dissolves,  evolving  a  great  quantity  of  nitrous  gas. 
On  allowing  the  liquid  to  cool,  a  large  quantity  of  semi-trans- 
parent yellow  crystals  is  formed  having  a  very  bitter  taste. 
This  is  what  was,  till  lately,  called  carbazotic  acid ;  but  this 
name  has  been  changed  to  picric  acid.  At  the  present  time 
picric  acid  is  manufactured  from  carbolic  acid,  found  in  coal 
tar. 

To  procure  it  in  a  purer  state,  the  crystals  obtained  by  the 
above  operation  are  to  be  washed  in  cold  water,  and  then 
boiled  in  water  sufficient  to  dissolve  them  ;  next  filtering  the 
liquid  and  allowing  it  to  cool.  The  acid  again  crystallizes  in 
brilliant  yellow  prisms.  The  acid  may  also  be  obtained  by 
the  action  of  nitric  acid  upon  anilic  acid. 

Picric  acid  is  very  permanent  in  its  constitution.  When 
fused  in  chlorine  or  wTith  iodine  it  is  not  decomposed,  nor  does 
a  solution  of  chlorine  affect  it.  Cold  sulphuric  acid  has  no 
action  upon  it,  but  dissolves  it  when  hot.  Boiling  hydro- 
chloric acid  does  not  act  upon  it,  but  nitromuriatic  acid  (aqua 
regia)  dissolves  it  with  difficulty.  It  acts  like  a  strong  acid 
upon  metallic  oxides,  dissolving  them  and  forming  peculiar 
crystallizable  salts.  These  are  yellow;  they  detonate  strongly 
when  sharply  heated,  and  also  by  percussion,  particularly  the 
salt  formed  with  potash.  When  a  little  of  it  is  gradually 
heated  in  a  glass  tube,  it  first  fuses  and  then  suddenly  ex- 
plodes, breaking  the  tube  to  pieces.  Care  is  necessary  in 
making  this  experiment,  as  the  fragments  of  glass  may  injure 
the  face. 

This  acid  is  an  excellent  test  for  the  presence  of  potash  in 
any  fluid  ;  a  solution  of  it  in  alcohol  producing  a  bright  yellow 
crystalline  precipitate  even  in  a  diluted  solution  of  the  alkali. 
It  is  thus  more  sensible  than  the  chloride  of  platinum,  com- 
monly employed  for  the  detection  of  potash ;  for  that  re-agent 
does  not  produce  a  precipitate  in  dilute  solutions. 

When  indigo  is  acted  upon  by  very  diluted  fuming  nitric 
acid,  it  unites  with  two  atoms  more  of  oxygen,  and  is  conse- 
quently converted  into  a  new  substance,  which  has  received 
the  name  of  isatine.  This  substance,  under  the  influence  of 
alkalies,  absorbs  one  equivalent  more  of  water,  and  assumes 
an  acid  character,  and  is  termed  isatinic  acid.  This  acid  com- 
bines with  other  substances,  forming  a  series  of  compounds 
the  nature  of  which  is  not  yet  very  well  known. 

Chromic  acid  has  a  similar  action  upon  indigo  as  nitric  acid. 

When  indigo  in  the  dry  state  is  brought  into  contact  with 


INDIGO  DYEING.  281 

dry  chlorine,  no  chemical  action  is  observed;  but  when  indigo 
suspended  in  water  is  subjected  to  the  action  of  chlorine, 
several  new  products  are  formed.  When  the  fluid  thus  acted 
upon  is  distilled,  a  fluid  product  in  minute  quantity  passes 
over  with  the  distilled  water,  and  collects  under  it  in  the  re- 
ceiver in  the  form  of  white  scales,  which  has  been  termed 
chlorindoptin.  It  is  sparingly  soluble  in  water,  but  copiously 
in  alcohol.  The  substance  which  remains  in  the  retort  is  found 
to  be  a  mixture  of  several  new  products.  On  being  dissolved 
in  boiling  alcohol,  it  yields,  on  cooling,  red  prismatic  crystals 
of  a  bitter  taste  and  very  insoluble  in  water;  this  has  been 
named  chlorisatin.  It  dissolves  in  a  solution  of  caustic  potash, 
producing  a  red  color.  The  salts  of  lead  give  with  this  solu- 
tion a  yellow  precipitate,  which  becomes  a  fine  scarlet  by 
standing.  The  salts  of  copper  (bluestone),  &c,  give  a  brown, 
which  becomes  blood-red  by  exposure  to  the  air.  In  the  alco- 
holic solution  another  substance  is  found,  having  an  equiva- 
lent more  of  chlorine  than  that  named  above;  this  is  termed 
bichlorisatin.  Its  properties,  however,  are  analogous  to  those 
of  chlorisatin ;  its  solution  in  potash  gives  a  yellow  precipitate 
with  the  salts  of  lead,  but  does  not  alter  by  exposure  to  the 
air;  and  with  the  copper  salts  it  gives  a  yellowish-brown, 
which  passes  to  blood-red.  When  chlorine  is  passed  through 
a  solution  of  chlorisatin,  another  substance  named  chloronile  is 
formed.  This  crystallizes  in  scales  of  a  brass-yellow  color,  and 
when  dissolved  by  potash  gives  a  beautiful  purple  color. 

If  indigo  in  powder  be  added  to  a  solution  of  caustic  potash 
of  specific  gravity  1.35  (70°  Twaddell)  and  boiled,  an  orange- 
yellow  salt  is  formed.  The  solution  of  the  boiled  mass  becomes 
blue  in  the  air  from  absorption  of  oxygen,  like  a  solution  of 
white  indigo,  and  blue  indigo  precipitates. 

Besides  the  compounds  resulting  from  the  action  of  nitric 
acid  and  chlorine  upon  indigo,  there  are  several  others  which, 
from  their  true  characters  being  still  little  known,  we  have 
not  thought  it  necessary  to  enumerate.  Some  practical  dyer 
may  indeed  be  inclined  to  ask  what  those  already  noticed  have 
to  do  with  dyeing?  We  are  sorry  that,  with  respect  to  some 
of  them,  we  cannot  give  any  satisfactory  answer  to  the  ques- 
tion ;  but  the  same  question  was  asked  when  chemists  first 
intimated  that  chromic  acid  produced  yellow  salts  when  com- 
bined with  lead;  yet  this  simple  hint  has  completely  revolu- 
tionized various  departments  of  dyeing,  and  the  action  of 
chrome  acid  upon  indigo,  as  already  observed,  has  been  both  a 
source  of  annoyance  and  advantage  to  the  dyer.  Previous  to 
the  use  of  alkaline  solutions  of  lead,  dyers  seldom  could  get 
an  evenly  chrome  green;  the  chromic  acid  being  set  at  liberty 


282 


INDIGO. 


acted  upon  the  indigo  which  was  upon  the  yarn,  destroying  in 
part  the  blue  color,  after  which  the  green  was  all  light-yellow 
blains.  These  annoyances  are  still  felt  where  the  new  process 
of  working  the  lead  solution  with  an  alkali  is  not  practised. 
But  this  same  action  of  chromic  acid  upon  indigo  has  been 
taken  advantage  of  by  calico-printers,  when  they  want  a  white 
pattern  on  a  blue  ground. 

Previous  to  the  introduction  of  bichromate  of  potash  for 
this  purpose,  the  calico-printers  were;  to  a  certain  extent, 
limited.    Thus : — 

The  pattern  is  printed  upon  the  cloth  with  the  oxide  of  a 
metal  which  yields  its  oxygen  easily  to  other  substances,  such 
as  copper  and  zinc;  the  goods  are  afterwards  dyed  blue  by 
passing  them  through  the  vat ;  but  the  parts  upon  which  these 
metallic  salts  are  printed,  resist  the  dye,  by  yielding  their 
oxygen  to  the  indigo,  a  process  which  will  afterwards  be  de- 
scribed, so  that  the  piece  when  finished  is  a  blue  ground  with 
a  white  pattern.  But  after  the  blue  vats  have  been  wrought 
for  some  time,  they  cannot  be  used  for  this  purpose,  owing  to 
the  weakness  of  the  dye,  and  the  consequent  length  of  time  ne- 
cessary to  produce  the  required  shade.  So  that  these  resist 
pastes  are  in  a  manner  washed  off,  and  the  pattern  spoiled. 
Now,  in  place  of  throwing  out  as  useless  vats  thus  exhausted, 
as  was  formerly  done,  the  cloth  is  dyed  blue  without  resists, 
and  after  being  slightly  scoured  and  washed,  it  is  passed 
through  a  strong  solution  of  chromate  of  potash,  and  dried  in 
the  shade ;  the  required  pattern  is  then  printed  on  the  cloth 
with  a  mixture  of  oxalic  and  tartaric  acids  made  into  a  paste 
by  gum  or  clay.  The  potash  in  union  with  the  chromic  acid 
is  taken  up  by  these  acids,  and  the  chromic  acid  being  set  at 
liberty,  acts  on  the  indigo,  and  a  white  pattern  is  produced. 
This  ingenious  process  was  discovered  by  a  German  chemist. 

The  following  table  exhibits  the  composition  of  those  sub- 
stances which  we  have  briefly  described  as  resulting  from  the 
action  of  nitric  acid  and  chlorine  upon  indigo.  It  may  be 
required  for  reference  : — 


Name. 

c. 

H. 

0. 

sr. 

c. 

Water. 

Indigo  .... 

16 

5 

2 

1 

0 

0 

Isatine  .... 

16 

5 

4 

1 

0 

0 

Isatinic  acid  . 

16 

5 

4 

1 

0 

l 

Anilic,  or  indigotic  acid  . 

14 

4 

9 

1 

0 

i 

Picric,  or  carbazotic  acid 

12 

2 

13 

3 

0 

i 

Chlorindoptin 

16 

4 

2 

0 

4 

0 

Chlorisatin 

16 

4 

3 

1 

1 

0 

Bichlorisatin  . 

16 

4 

3 

1 

2 

0 

Chloranile 

6 

0 

2 

0 

2 

0 

Valerianic  acid 

10 

9 

3 

0 

0 

1 

SULPHO-PURPURIC  ACID. 


283 


The  only  substance  which  dissolves  indigo,  without  destroy- 
ing its  color  and  composition,  is  highly  concentrated  sulphuric 
acid.  For  this  purpose  the  fuming  acid  of  Nordhausen  is  pre- 
ferable (page  96),  as  when  other  acid  is  used,  a  greater  quan- 
tity of  it  is  required.  The  substance  formed  is  popularly 
known  by  the  names  of  sulphate  of  indigo,  Saxon  blue,  China 
blue,  and  extract  of  indigo.  The  action  of  sulphuric  acid  upon 
indigo  is  found  to  be  something  more  than  a  mere  solution  ;  a 
chemical  combination,  in  definite  proportions,  results,  forming 
two  distinct  substances,  differing  considerably  from  each  other 
in  their  properties.  These  two  compounds  were  discovered 
and  described  by  Mr.  Crum,  and  called  by  him  cerulin  and 
phinacint  from  their  colors — the  former  blue,  and  the  latter 
purple.  They  have  since  been  named  sulph-indylic  acid,  and 
sulpho-purpuric  acid.  The  former,  which  constitutes  the  blue 
principle  of  Saxon  blue,  is  formed  most  abundantly  when  the 
sulphuric  acid  is  sufficiently  strong  and  abundant,  and  other 
proper  means  attended  to.  Its  composition  is  found  to  be  one 
atom  of  indigo  combined  with  two  of  sulphuric  acid.  The 
other  is  the  principal  product  when  the  indigo  preponderates. 

It  is  of  a  purple  color ;  and  when  the  solution  is  diluted  with 
water,  it  precipitates.  Its  composition  is  found  to  be  equal  to 
one  atom  of  indigo  to  one  of  sulphuric  acid. 

From  the  nature  and  properties  of  these  two  substances,  it 
is  evident  that  every  care  should  be  taken  to  convert  the  in- 
digo into  sulph-indylic  acid,  and  to  avoid  the  formation  of 
sulpho-purpuric  acid.  The  circumstances  under  which  this 
latter  acid  is  formed  are — first,  too  little  acid  in  proportion  to 
the  indigo,  and  secondly,  too  little  time  allowed  for  digestion. 
The  general  proportions  used  by  dyers  vary  from  three  to  five 
pounds  of  acid  to  the  pound  of  indigo.  This  is  by  far  too  lit- 
tle, and  occasions  a  considerable  loss  of  indigo  by  the  precipi- 
tation of  the  sulpho-purpuric  acid,  when  the  solution  is  diluted 
with  water.  Close  observation  shows  that  it  requires  from  six 
to  eight  pounds  of  concentrated  sulphuric  acid  to  convert  a 
pound  of  indigo  into  blue  sulph-indylic  acid.  From  some  in- 
vestigations lately  made  by  M.  Dumas,  indigo  requires  even  a 
larger  proportion  of  acid  to  convert  it  into  sulph-indylic  acid. 
He  recommends  no  less  than  fifteen  parts  of  acid  to  one  of  in- 
digo. This  quantity,  however,  we  have  found  to  be  of  no 
advantage  in  practice,  but  rather  the  opposite,  particularly  when 
the  acid  is  to  be  neutralized  before  the  indigo  solution  is  used, 
which  is  the  general  custom  in  dyeing  cotton. 

We  have  said  that  the  second  circumstance  under  which 
sulpho-purpuric  acid  is  formed  is  that  of  too  short  time  being 
given  for  the  indigo  and  acid  to  digest.    When  indigo  is  first 


284 


INDIGO. 


put  into  the  sulphuric  acid,  there  seems  to  be  an  immediate 
solution  ;  but  if  a  drop  be  spread  upon  a  window-pane,  it 
appears  of  a  dirty-green  color  ;  and  if  allowed  to  stand  for  a 
little  upon  the  glass,  a  yellowish-colored  liquid  begins  to  run 
from  the  blue  mass,  occasioned,  no  doubt,  by  the  acid  absorb- 
ing moisture,  and  separating  itself  from  the  indigo,  and  clearly 
showing  that  the  change  upon  the  indigo  by  the  acid  is  not  an 
immediate  effect.  The  more  impure  the  indigo,  the  darker  and 
greener  appears  the  substance  when  put  upon  the  glass.  After 
the  mixture  has  stood  two  or  three  hours,  and  being  tried  in 
the  same  manner,  it  appears  of  a  reddish-purple  color — the 
principal  compound  existing  now  in  the  solution  being  sulpho- 
purpuric  acid.  As  the  liquid  stands,  it  begins  to  assume  a 
violet  shade,  and  finally  passes  to  a  deep  rich  blue.  But  dyers 
seldom  obtain  it  in  this  state ;  in  their  hands  it  generally  has  a 
reddish  tinge.  Mr.  Crum  found  that  when  the  solution  is 
diluted  with  water,  after  the  color  has  become  of  a  bottle-green, 
the  action  of  the  acid  is  stopped,  and  sulpho-purpuric  acid  only 
is  formed.  But  there  are  other  means  by  which  the  action  of 
sulphuric  acid  upon  indigo  may  be  stopped,  than  by  directly 
diluting  the  solution  with  water.  As  already  intimated,  it  is 
only  the  highly  concentrated  sulphuric  acid  which  converts  in- 
digo into  sulph-indylic  acid.  Now,  dyers  not  unfrequently 
alter  the  strength  of  their  acid  by  the  process  of  mixing  and 
preparing  their  chemtc  (the  technical  name  for  sulphate  of  in- 
digo). This  is  very  generally  done  in  an  open  wide-mouthed 
vessel,  which  is  allowed  to  stand  uncovered,  probably  in  the 
midst  of  the  steam  and  vapors  of  the  dye-house ;  or,  in  some 
cases,  the  vessel  is  put  into  a  boiler,  or  tub  with  boiling  water. 
By  these  injudicious  means,  the  sulphuric  acid  which  absorbs 
water  very  rapidly,  is  diluted  below  the  necessary  strength 
for  dissolving  indigo ;  and  the  result  is  the  formation  of  sulpho- 
purpuric  acid,  instead  of  sulph-indylic  acid,  which  is  the  real 
substance  wanted. 

Another  cause  of  the  stopping  of  the  action  of  the  acid  by 
dilution  is  from  the  indigo.  Ground  indigo  absorbs  a  quan- 
tity of  moisture;  and  if  it  be  not  thoroughly  dried  previous  to 
putting  it  in  the  acid,  the  acid  is  too  much  weakened  to  effect 
the  formation  of  the  substance  required. 

There  are  other  causes  by  which  the  preparation  of  chemic  is 
injured.  Sometimes  the  acid  and  indigo  are  mixed  together 
at  once,  and  by  this  means  the  heat  evolved  is  sufficient  to  de- 
compose the  impurities  of  the  indigo.  Part  of  the  acid  also 
suffers  decomposition,  and  a  great  quantity  of  sulphurous  acid 
gas  is  given  off — so  much,  indeed,  that  the  head  cannot  be 
held  above  the  vessel  for  any  length  of  time  without  injury. 


SULPHATE  OF  INDIGO. 


285 


Another  practice  is,  for  the  sake  of  quickening  the  operation, 
to  place  the  vessel  upon  the  flue  in  the  stove,  and  keep  the 
solution  for  hours  at  a  heat  upwards  of  300°  Fah.  The  gas 
given  off  in  these  cases  is  sometimes  so  great  as  to  destroy  the 
colors  of  goods  hanging  in  the  stove.  Indigo  submitted  to  such 
treatment  is  seldom  found  good ;  often  its  appearance  on  white 
paper  or  glass  (which  is  a  general  method  of  testing  the  quality 
of  sulphate  of  indigo)  is  a  blackish-green — sometimes  a  dirty 
purple — seldom  the  fine  blue  violet — scarcely  ever  the  beau- 
tiful blue. 

Although  the  sulpho-purpuric  acid  is  precipitated  when 
water  is  mixed  with  the  solution  of  sulphate  of  indigo,  and  is 
insoluble  in  dilute  acids,  it  is,  when  freed  from  the  sulphuric 
acid,  soluble  in  distilled  water;  but  if  any  substance  be  in 
the  water — and  common  spring  water  is  never  pure — it  is  less 
soluble.  It  dissolves  in  alkalies,  and  in  solutions  of  the  alka- 
line earths,  giving  a  blue  color,  of  greater  or  less  purity,  ac- 
cording to  the  nature  of  the  solvent. 

We  have  found  the  following  method  of  preparing  sulphate 
of  indigo,  in  quantities  for  use,  very  satisfactory :  The  indigo 
is  reduced  to  an  impalpable  powder,  either  by  grinding  in  a 
mortar  or  a  mill,  and  completely  dried,  by  placing  it  upon  a 
sand-bath  or  flue  for  some  hours,  at  a  temperature  of  about 
140°  or  150°  Fah.  For  each  pound  of  indigo,  six  pounds  of 
highly  concentrated  sulphuric  acid  are  put  into  a  large  jar,  or 
earthen  pot,  furnished  with  a  cover.  This  is  kept  in  as  dry  a 
part  as  possible,  and  the  indigo  is  added  gradually,  in  small 
quantities.  The  vessel  is  kept  closely  covered,  and  care  taken 
that  the  heat  of  the  solution  does  not  exceed  212°  Fah.  When 
the  indigo  is  all  added,  the  vessel  is  placed  in  such  a  situation 
that  the  heat  may  be  kept  at  about  150°  Fah.,  and  allowed  to 
stand,  stirring  occasionally,  for  forty-eight  hours.  These  pre- 
cautions being  attended  to,  we  have  uniformly  found  that  any 
failure  occurring  was  clearly  traceable  to  impurity  of  the  indigo 
or  weakness  of  the  acid  used. 

The  dyer  now  very  seldom  prepares  his  own  sulphate  of  in- 
digo; it  is  manufactured  for  him,  and  sold  in  the  market  as 
indigo  extract,  which,  when  properly  prepared,  is  a  superior 
article  to  that  prepared  by  himself.  The  following  is  the  pro- 
cess of  its  manufacture:  The  indigo  is  dissolved  in  the  sul- 
phuric acid  as  described ;  it  is  then  diluted  with  hot  water — 
distilled  water  is  best;  the  whole  is  put  upon  a  filter  of  woollen 
cloth,  by  which  means  the  insoluble  impurities  of  the  indigo 
are  separated.  The  blue  solution  which  has  passed  through 
the  filter  is  transferred  to  a  leaden  vessel,  and  evaporated  till 
reduced  to  about  three  gallons  for  every  pound  of  indigo  used. 


286 


INDIGO. 


There  is  then  added  about  4  lbs.  of  common  salt  to  the  pound 
of  indigo,  and  the  whole  is  well  stirred.  The  sulpho  indylic 
acid  is  thus  precipitated,  and  the  whole  is  again  thrown  upon 
a  similar  filter  of  woollen  cloth;  the  extract  remains  upon  the 
filter,  and,  when  sufficiently  drained,  is  ready  for  the  market. 
Some  makers  add  a  little  potash  or  soda,  which  may  be  ad- 
vantageous, and  a  little  ammonia  gives  the  extract  a  beautiful 
bloom.  A  pound  weight  of  good  indigo  should  yield  14  lbs. 
of  extract.  The  adulterations  in  this  solution  are  various. 
Some  of  the  insoluble  matter  is  occasionally  added,  bat  not 
often,  as  it  deteriorates  the  appearance  of  the  extract.  The  ad- 
dition of  a  little  lime  or  barytes  gives  an  insoluble  precipitate, 
which  adds  weight  to  the  extract;  but  all  practices  of  that 
kind  react  upon  the  maker ;  for,  although  the  dyer  may  not 
have  methods  of  testing  his  stuff,  he  very  soon  ascertains  its 
working  value  by  experience. 

The  extract  of  indigo  is  used  in  the  dye-house  in  the  same 
way  as  the  sulphate  was  used  before  this  method  of  preparation 
was  adopted.  The  general  term  of  chemic  is  applied  to  both, 
and  chemic  blue  is  used  in  various  operations.  For  dyeing 
silks  and  woollens  blue,  the  extract  is  simply  diluted,  and  the 
goods  merely  passed  through  it ;  but  this  method  cannot  be 
adopted  with  cotton,  as  its  fibres  have  no  affinity  for  sulphate 
of  indigo.  But  although  not  used  for  dyeing  blue  upon  cot- 
ton, it  is  extensively  used  for  dyeing  green  upon  light  goods 
of  that  material.  When  the  cloth  is  dried  from  the  sulphate 
of  indigo  solution,  the  acid  of  the  chemic  must  be  neutralized ; 
for  this  purpose  the  chemic  is  prepared  differently.  The  ex- 
tract is  put  into  hot  water — the  exact  quantity  is  not  material — 
and  well  stirred ;  to  this  solution  a  quantity  of  pounded  chalk 
or  whiting  is  added  gradually,  until  the  acid  is  exactly  neu- 
tralized ;  this  is  a  nice  operation,  and  requires  great  care  on  the 
part  of  the  operator;  for,  were  the  acid  property  to  prevail  in 
the  least,  it  would  destroy  the  yellow  upon  the  cloth  to  be  dyed 
green;  and  were  the  alkaline  matter  predominant,  it  would 
brown  the  yellow,  and  the  green  would  assume  a  blackish- 
olive  shade.  Thus  the  beauty  of  the  colors  depends  upon  the 
dyer  being  careful  to  stop  just  at  the  turning  point.  The  only 
method  employed  by  dyers  for  determining  the  point  of  neu- 
trality is  the  taste;  and  this,  from  many  circumstances  which 
we  need  not  enumerate,  is  liable  to  error;  and  when  the  dyer 
is  deceived,  the  results  are  very  annoying,  and  also  expensive. 
Were  very  delicately  prepared  blue  and  red  litmus-papers 
used,  the  results  would  be  much  more  certain.  However,  the 
reader  may  be  astonished  when  we  inform  him,  that  the  failures 
from  this  source  are  very  seldom.    Some  dyers  use  carbonated 


THE  BLUE  VAT. 


287 


alkalies,  such  as  soda  and  potash,  to  neutralize  their  acid ;  and 
no  doubt  when  any  of  these  are  used,  the  sediment  at  the  bot- 
tom is  much  less;  but  we  have  always  thought  that  owing  to 
the  salts  formed  by  these  alkalies  being  dissolved  in  the  blue 
solution,  the  green  color  is  not  so  good,  especially  when  bark 
is  the  yellowing  substance. 

The  process  of  dyeing  greens  by  this  sort  of  prepared  chemic 
is  as  follows:  The  goods,  after  being  well  boiled  and  washed, 
are  put  through  a  dilute  solution  of  pyrolignite  of  alumina  of 
specific  gravity  1.035,  that  is  7°  of  Twaddell,  and  washed  from 
this  through  hot  water;  they  are  then  wrought  through  a  de- 
coction of  quercitron  bark,  or  jlavine.  When  sufficiently  yellow 
for  the  shade  of  green  required,  they  are  then  wrought  through 
a  quantity  of  chemic  mixed  with  cold  water,  wrung  from  this 
and  dried.  If  fustic  is  the  yellowing  substance  used,  alum  is  a 
better  mordant. 

The  greater  portion  of  the  indigo  imported  is  used  for  dye- 
ing blue  by  means  of  the  blue  vat.  We  have  already  men- 
tioned that  indigo  is  insoluble,  except  in  strong  sulphuric  acid; 
but  if  it  be  by  any  means  deprived  of  an  atom  of  oxygen  (ac- 
cording to  the  common  theory),  it  is  soluble  in  alkalies.  It 
may  be  said  that,  according  to  the  law  of  definite  proportions 
described  in  our  first  article,  it  cannot  be  indigo  with  an  atom 
less  of  oxygen.  Neither  is  it;  and  we  see  that  it  has  different 
properties  from  common  indigo,  for  it  is  soluble  even  in  weak 
alkalies;  has  a  powerful  attraction  for  oxygen;  and  is  of  a  white 
color.  This  substance  has  been  termed  indigogen,  and  it  may 
be  observed,  that  the  nature  of  the  blue  vat  depends  upon  the 
introduction  of  substances  capable  of  extracting  oxygen  from 
the  indigo,  and  converting  it  into  indigogen.  The  substances 
generally  used  for  this  conversion  are  the  protoxides  of  iron 
and  tin,  orpiment  (sulphuret  of  arsenic),  and  organic  substances. 
These  last  produce  the  desired  effect  by  their  decomposition, 
such  as  in  the  woad  vat,  where,  by  the  fermentation  of  the 
woad  and  madder,  the  oxygen  is  extracted  from  the  indigo, 
which  is  thus  converted  into  indigogen.  The  indigogen  is  dis- 
solved, as  it  forms,  by  the  potash  put  into  the  vat. 

What  is  termed  the  common  blue  vat,  or  lime  vat,  is  made 
up  with  indigo,  lime,  and  sulphate  of  iron  (copperas).  But 
before  describing  the  nature  of  this  vat  it  will  be  necessary,  at 
the  risk  of  a  little  repetition,  to  refer  to  the  properties  of  oxide 
of  iron  (page  152). 

The  protoxide  of  iron,  especially  when  in  contact  with  mois- 
ture, has  a  strong  attraction  for  more  oxygen  so  as  to  pass  into 
the  peroxide.  When  the  sulphuric  acid  of  copperas  is  neutral- 
ized by  an  alkali,  the  iron  is  left  in  the  state  of  a  protoxide. 


288 


INDIGO. 


The  blue  vat  is  made  up  by  putting  lime,  copperas,  and  indigo 
into  a  vessel  filled  with  water,  and  stirring  occasionally  for  a 
day  or  two,  when  the  indigo  is  dissolved.  Thus:  When  finely 
ground  indigo  is  put  into  a  vat  with  a  mixture  of  lime  and 
sulphate  of  iron,  the  first  action  which  takes  place  is  the  de- 
composition of  the  metallic  salt;  the  acid,  which  is  in  union 
with  the  iron,  combining  with  a  portion  of  the  lime,  forms  sul- 
phate of  lime  and  oxide  of  iron.  The  detached  oxide  of  iron 
extracts  more  oxygen  from  the  indigo,  converting  it  into  indi- 
gogen  (white  indigo),  and  the  peroxide  of  iron  and  the  sulphate 
of  lime  thus  formed  are  precipitated,  forming  what  is  technically 
termed  sludge.  The  remaining  portion  of  lime  dissolves  the  in- 
digogen,  and  forms  with  it  the  solution  required.  The  follow- 
ing diagram  represents  this  action  and  the  result  more  clearly, 
and  gives  one  view  of  the  theory  of  the  blue  vat: — 


J  Indigogen 
(Oxygen 


Indigo,  composed  of 

f  Oxide  of  iron  - 
J  Oxide  of  iron 
Sulphuric  acid 
Sulphuric  acid 

(  Lime  

3  Lime  •<  Lime  


2  Copperas 


Dyeing  solution. 


Peroxide  of  iron. 


(  Lime . 


Sulphate  of  lime. 
Sulphate  of  lime. 

It  will  be  observed  that  this  theory  of  the  vat  is  founded  on 
blue  indigo  being  an  oxide;  but,  according  to  the  view  which 
Dumas  takes  of  the  constitution  of  indigo,  the  action  which 
takes  place  in  the  vat  will  be  somewhat  different  from  that 
given  above.  When  the  lime  combines  with  the  acid  of  the 
copperas,  the  iron  decomposes  a  portion  of  water,  combining 
with  the  oxygen,  and  the  hydrogen  combines  with  the  indigo 
forming  indigogen,  which  may  be  represented  as  follows: — 


Indigo . 
Water  . 

3  Lime. 


2  Copperas. 


.  Indigo  

J  Hydrogen.  .  .  . 

(Oxygen  

(Lime  

-<  Lime  

(Lime  

[  Oxide  of  iron. 
J  Oxide  of  iron. 
J  Sulphuric  acid 
[  Sulphuric  acid 


Indigogen,  forming  dyeing 
solution. 


Peroxide  of  iron. 
Sulphate  of  lime. 
Sulphate  of  lime. 


This  theory  is  equally,  if  not  more  beautiful,  than  the  former, 
but  in  some  cases  it  is  scarcely  reconcilable  with  our  chemical 
experience.   When  the  goods  are  put  into  the  vat,  the  dissolved 


THEORY  OF  THE  BLUE  VAT. 


289 


indigogen  combines  with  them,  and  when  brought  into  contact 
with  the  air,  according  to  the  former  theory,  the  indigogen 
combines  with  oxygen,  for  which  it  has  a  strong  affinity 
and  blue  indigo  is  formed,  and  remains  combined  with  the 
cloth;  but,  according  to  the  latter  theory,  the  blue  indigo  is 
left  in  combination  with  the  cloth  by  the  hydrogen  combining 
with  the  oxygen  of  the  atmosphere,  and  forming  water.  The 
supposition  that  hydrogen  should  combine  with  the  free  oxygen 
of  the  air,  and  form  water  so  rapidly  under  such  circumstances 
as  mere  exposure,  is  somewhat  anomalous,  but  this  is  no  reason 
for  rejecting  it.  If  a  mixture  of  copperas  and  lime  be  put 
into  a  bottle  with  distilled  water,  the  water  is  not  decomposed  ; 
the  lime  combines  with  the  acid,  which,  along  with  the  iron,  is 
precipitated,  and  if  the  air  be  completely  excluded,  the  iron 
remains  as  a  protoxide,  for  days ;  indeed,  the  change  from  a 
protoxide  to  a  peroxide  is  so  slow,  that  a  long  time  elapses 
before  it  is  appreciable;  but  if  indigo  be  added,  even  after  the 
mixture  has  stood  for  some  time,  the  action  of  the  common  vat 
proceeds.  This,  according  to  Dumas's  theory,  gives  a  beautiful 
illustration  of  relative  affinities.  Before  the  indigo  is  introduced, 
the  attraction  of  the  iron  for  oxygen  is  about  equal  to  that  of 
the  hydrogen,  which  holds  it  in  combination  as  water,  but  when 
the  indigo  is  introduced,  although  its  attraction  for  hydrogen 
must  be  very  weak,  as  it  requires  the  nicest  management  to  get 
that  compound  isolated,  still  it  is  sufficient  to  disturb  the  equi- 
librium with  which  the  oxygen  was  held  by  the  iron  and  hydro- 
gen, giving  the  former  the  mastery.  Whether  the  presence  of 
an  alkaline  substance  has  any  effect  of  inducing,  if  we  be 
allowed  the  term,  the  formation  of  indigogen,  we  cannot  pre- 
tend to  determine;  but  it  is  never  formed  in  the  vat  without 
the  presence  of  some  alkaline  substance  to  dissolve  it  the 
moment  it  is  formed.  This  circumstance  also  explains  that  the 
alkali  having  also  an  affinity  for  indigogen,  may  assist  the 
reaction  in  the  vat. 

We  would  recommend  the  reader  to  reperuse  the  remarks 
upon  the  salts  of  iron,  in  connection  with  these  on  the  blue  vat, 
in  order  that  he  may  be  better  able  to  appreciate  them,  and 
especially  to  understand  what  ought  to  be  the  properties  of 
good  copperas  from  the  part  it  is  required  to  play  in  the  vat; 
also  why  it  is  that  the  quality  of  the  copperas  makes  so  great 
a  difference  in  the  working  of  a  blue  vat. 

There  is  one  serious  annoyance  often  experienced  in  working 
the  vat,  technically  called  swimming ;  that  is,  the  precipitate 
not  settling  down,  the  goods  come  in  contact  with  it  to  the 
serious  injury  of  the  color.  This  may  be  occasioned  by  several 
circumstances.  Should  the  copperas  have  an  excess  of  acid, 
19 


290 


INDIGO. 


either  from  its  being  crystallized  out  of  an  acid  solution,  or  from 
its  having  sulphate  of  alumina  in  it  (as  described  at  page  155), 
it  will  form  a  sulphate  of  lime,  which  will  not  precipitate  so 
quickly  as  that  formed  by  the  decomposition  of  the  copperas ; 
but  the  prevailing  cause  of  a  floating  vat  is  excess  of  iron  and 
lime.  Let  the  dyer  take  a  solution  of  copperas  or  protosul-  , 
phate  of  iron,  and  one  of  persulphate,  and  add  to  each  a  suffi- 
cient quantity  of  lime  to  precipitate  the  iron,  he  will  find  that 
the  peroxide  of  iron  will  precipitate  rapidly  and  completely, 
and  that  the  protoxide  will  precipitate  slowly  and  incompletely. 
The  same  phenomenon  takes  place  in  the  vat  when  lime  and 
copperas  are  added  ;  sulphate  of  lime  and  protoxide  of  iron 
are  formed,  and  if  there  be  not  enough  of  indigo  to  convert 
the  protoxide  of  iron  to  the  state  of  peroxide — in  which  state 
it  precipitates  easily — the  protoxide  will  remain  floating  for  a 
long  time.  Hence  the  floating  vat — the  only  cure  for  which 
is  the  addition  of  a  little  indigo,  or  of  a  substance  that  will 
peroxidize  the  iron.  When  vats  become  weak,  great  care 
should  be  taken  not  to  add  an  excess  of  copperas.  We  have 
seen  a  little  soda  added  to  a  floating  vat  as  a  cure,  and  if  the 
evil  consisted  in  the  quantity  of  the  copperas,  this  mode  of  cure 
might  be  successful,  but  not  otherwise.  A  floating  vat  is 
sometimes  caused  by  using  improper  lime.  When  slaked  lime 
lies  exposed  for  a  short  time  to  the  air,  and  more  especially  in 
a  work  such  as  a  dye-work,  it  absorbs  carbonic  acid,  and  be- 
comes converted  into  chalk,  and  this  put  into  the  vat  is  very 
deleterious  in  other  respects,  besides  causing  swimming.  The 
lime  used  for  the  vat  should  always  be  newly  slaked.  This  is  a 
necessary  precaution,  as  the  practice  is  too  often  otherwise  that 
is  here  recommended. 

When  the  paucity  of  indigo  in  the  last  stages  of  a  vat  causes 
floating,  a  small  portion  of  a  copper  salt  may  be  of  service,  as 
this  oxide  will  give  up  a  part  of  its  oxygen  to  the  iron,  becom- 
ing a  suboxide;  or  it  will  oxidate  a  portion  of  the  indigo  in 
solution,  and  this  would  react  in  turn  upon  the  iron.  The 
property  of  this  and  some  other  metals  for  neutralizing  the 
effects  of  iron  in  the  vat  has  already  been  noticed ;  but  it  may 
be  more  apparent  by  thus  referring  to  it- here,  and  it  may  be 
still  farther  enforced  in  connection  with  that  branch  of  calico- 
printing  called  resist  work,  indicated  at  page  282,  and  which 
may  be  thus  further  described :  A  certain  preparation,  the  best 
we  believe  is  the  sulphate  of  copper  or  zinc,  is  mixed  either 
with  flour  paste,  with  gum,  or  writh  pipe-clay  and  gum,  and 
printed  on  the  calico,  of  any  pattern  that  may  be  desired  ;  when 
this  is  sufficiently  dry,  the  goods  are  dyed  in  the  blue  vat  ; 


THE  BLUE  VAT. 


291 


those  parts  of  the  piece  which  are  printed  with  the  copper  or 
zinc  will  not  be  dyed  blue,  because  the  deoxidized  indigo  be- 
comes oxygenated  the  moment  it  touches  the  copper,  which 
yields  its  oxygen  to  the  indigo,  and  occasions  it  to  become 
insoluble,  and  consequently  incapable  of  forming  a  dye.  Ac- 
cording to  Dumas's  theory,  the  hydrogen,  in  combination  with 
the  indigo,  unites  with  the  oxygen  of  the  copper  and  forms 
water — the  results  are  alike  in  both. 

Before  concluding  this  article,  we  may  inform  the  general 
reader  that,  in  print-works  and  dye-houses,  where  piece-goods 
are  dyed  blue,  the  vats  are  necessarily  large,  being  generally 
about  three  feet  wide  by  five  feet  long,  and  eight  feet  deep, 
made  of  iron,  but  sometimes  of  stone;  and  are  sunk  into  the 
ground  about  half  their  depth.  The  goods  to  be  dyed  are 
stretched  upon  a  frame,  when  the  whole  is  lowered  into  the  vat. 
Sometimes  these  frames  are  furnished  with  rollers,  when,  instead 
of  fixing  the  piece  on  hooks,  it  is  passed  over  these  rollers  while 
in  the  vat,  by  which  means  long  pieces  are  dyed  perfectly 
regular  in  color. 

The  vats  for  yarn  or  skein  are  small,  being  generally  old 
wine  or  oil-pipes  ;  these  are  also  sunk  about  half  their  depth 
into  the  ground.  Wooden  pins  are  put  through  the  skein,  and 
rest  upon  the  edge  of  the  vat;  the  skein  is  then  turned  over, 
the  one  half  dipping  in  the  liquor,  the  other  half  over  the  pins. 
The  time  of  this  operation  varies  according  to  the  strength  of 
the  vat.  The  operation  being  continued  some  time,  the  skein 
is  taken  out,  wrung,  and  exposed  to  the  air,  dipped  again,  and 
so  on,  alternately  dipping  and  exposing,  till  the  requisite  shade 
is  obtained. 

To  prepare  the  vat,  it  is  filled  to  within  a  few  inches  of  the 
mouth  with  water ;  the  dyeing  ingredients  are  then  added.  The 
proportions  given  in  most  chemical  books  are  1  part  (by  weight) 
indigo,  2  parts  sulphate  of  iron,  and  3  parts  lime:  but  this  pro- 
portion of  lime  is  too  much  ;  the  practical  dyer  does  not  con- 
sider his  vats  in  good  condition  when  this  proportion  is  used. 
The  following  proportions  are  considered  proper  for  preparing 
one  of  these  small  vats — assuming  all  the  ingredients  good  :  8 
pounds  of  indigo,  14  pounds  of  copperas,  and  from  18  to  20 
(not  above  20)  of  lime.  If  the  copperas  be  bad,  a  pound  or 
even  2  pounds  more  of  it  may  be  required,  together  with  2  or  3 
additional  pounds  of  lime,  to  produce  the  same  result.  These  in- 
gredients being  put  in,  the  whole  is  well  stirred  every  two  or 
three  hours  during  the  day,  and,  after  settling  for  twelve  hours, 
the  vat  is  ready  for  use. 

The  chemical  equivalents  of  lime  may  be  calculated  from  the 


292 


INDIGO, 


table  of  elements,  and  also  the  rate  of  combination.  Thus, 
slaked  lime  is  the  hydrated  oxide  of  calcium: — 


Lime 
Water 


Ca 

=  20 

0 

=  8 

H 

0 

=  8 

37 

Fe 

=  28 

And  again  we  have — 

C°PPeras Is64  =48 
Water  of  crystallization   7 HO  =  63 

139 

Thus  by  equivalents,  37  lbs.  of  slaked  lime  should  neutralize 
139  lbs.  of  crystals  of  copperas;  but,  as  77  gallons  of  water  at 
60°  can  dissolve  only  one  pound  of  lime,  it  is  easy  to  see  how 
few  pounds  are  required  above  the  equivalent  for  copperas  to 
form  the  lime  solution  of  the  vat  to  dissolve  the  indigogen. 
How  it  is  that  practice  dictates  such  a  quantity  of  lime  to  be 
used,  is  deserving  of  inquiry ;  we  merely  hint  that  it  may  be 
that  the  compound  of  indigogen  and  lime  is  more  soluble  than 
lime  alone. 

Woad  and  Pastel. — We  have  already  alluded  to  these 
vegetables  as  yielding  a  variety  of  indigo  which  has  been  long 
used  for  dyeing  woollen  goods.  It  is  still  extensively  used  for 
that  purpose,  especially  on  the  continent ;  and  as  a  description 
of  the  process  as  it  is  there  followed  out  may  be  interesting  to 
many  of  our  readers,  we  extract  the  following  from  Dumas's 
Lectures  on  Dyeing,  slightly  altered  from  the  translation  in  the 
Pharmaceutical  Times  :— 

"  Indigo  Blue. — We  give  a  solid  dye  of  indigo  blue  to  wool 
by  plunging  it  into  an  alkaline  solution  of  indigo  white,  and 
then  exposing  it  to  contact  with  the  air.  The  solution  of  in- 
digo white  is  prepared  in  a  vessel  usually  from  eight  to  nine 
feet  in  depth,  and  six  to  seven  feet  in  diameter.  This  size  is 
very  convenient  for  the  requisite  manipulations,  and  presents  a 
large  volume  of  water,  which,  when  once  heated,  is  capable  of 
preserving  a  high  temperature  for  a  long  time.  This  vessel 
should  be  made  of  wood  or  copper.  It  always  bears  the  name 
of  vat.  These  vats  are  covered  with  a  wooden  lid,  divided 
into  two  or  three  equal  segments.  Over  this  lid  are  spread 
some  thick  blankets.  Without  this  precaution  the  bath  would 
come  in  contact  with  the  atmospheric  air;  a  portion  of  the 


WOAD  AND  PASTEL. 


293 


indigo  would  absorb  oxygen  and  become  precipitated.  There 
would  also  be  a  great  waste  of  heat. 

"  A  most  necessary  operation,  and  one  which  has  to  be  fre- 
quently repeated,  consists  in  stirring  up  the  deposit  of  vegetable 
and  coloring  matter  which  is  formed  in  the  vat,  and  intimately 
mixing  it  in  the  bath.  For  this  purpose  we  employ  a  utensil 
called  a  rake,  which  is  formed  of  a  strong  square  piece  of  wood, 
set  on  a  long  handle.  The  workman  takes  hold  of  this  with 
both  hands,  and,  dipping  the  flat  surface  into  the  deposit  at  the 
bottom  of  the  vessel,  he  quickly  draws  it  up  until  it  nearly 
reaches  the  surface,  when,  giving  it  a  gentle  shake,  he  dis- 
charges the  matter  again  through  the  liquor  of  the  bath.  This 
manoeuvre  is  repeated  until  the  whole  of  the  deposit  seems  to 
be  removed  from  the  bottom  of  the  vessel.  Before  the  tissue 
is  dipped  into  the  dye-bath,  it  should  be  soaked  in  a  copper 
full  of  tepid  water;  it  is  then  to  be  hung  up  and  beaten  with 
sticks.  In  this  state  it  is  plunged  into  the  vat  ;  it  thus  intro- 
duces less  air  into  the  bath,  while  it  is  more  uniformly  pene- 
trated by  the  indigo  solution.  The  cloth  is  now  kept  at  a 
depth  of  from  two  to  three  feet  below  the  surface  of  the  liquid, 
by  means  of  an  open  bag  or  piece  of  network  fixed  in  the  in- 
terior of  an  iron  ring,  which  is  suspended  by  cords,  and  fixed 
to  the  outside  of  the  vat  by  means  of  two  small  iron  hooks ; 
the  bag  is  thus  drawn  backwards  and  forwards  without  permit- 
ting it  to  come  in  contact  with  the  air.  When  this  operation 
has  been  continued  for  a  sufficient  length  of  time,  the  cloth  is 
wrung  and  hung  up  to  dry. 

"  Flock  wool  is  also,  for  the  purpose  of  dyeing,  inclosed  in 
a  fine  net,  which  prevents  the  least  particle  from  escaping,  and 
which  is  fixed  in  the  bath  in  the  same  way  as  in  the  foregoing 
case. 

"The  many  inconveniences  attending  the  use  of  wooden 
baths,  which  necessitate  the  pouring  of  the  liquor  into  a  copper 
for  the  purpose  of  giving  it  the  necessary  degree  of  heat,  have 
led  to  the  general  employment  of  copper  vessels.  These  are 
fixed  in  brickwork,  which  extends  half  way  up  their  surface, 
whilst  a  stove  is  so  constructed  at  this  elevation  that  the  flame 
shall  play  around  their  upper  part.  By  this  means  the  bath 
is  heated  and  kept  at  a  favorable  temperature  without  the 
liquor  being  obliged  to  be  removed. 

u  The  potash  vats  are  usually  formed  of  conical -shaped  cop- 
pers, surrounded  by  a  suitable  furnace.  These  may  be  con- 
structed with  less  depth,  inasmuch  as  there  is  less  precipitation 
induced  in  the  liquor.  By  using  steam  for  heating  the  vats, 
we  might  dispense  with  the  employment  of  copper  vessels,  and 
so  return  to  those  of  wood. 


29i 


INDIGO. 


uThe  vats  employed  for  dyeing  wool  are  known  under  the 
names  of  the  pastel  vat,  the  woad  vat,  the  potash  vat,  the  Tartar 
lee  vrat,  and  the  German  vat. 

"  The  pastel  is  cultivated  in  France,  Piedmont,  England,  and 
Saxony.  It  is  distinguished  into  several  varieties,  according 
to  the  localities  in  which  it  is  grown.  We  have  already  stated 
that  the  pastel  contains  a  blue  coloring  matter  identical  with 
indigo,  and  a  fawn-colored  yellow  matter,  which  may  easily  be 
separated  by  treating  the  pastel  balls  by  hot  water  before  the 
fermentative  process  is  established.  The  woad  is  cultivated  in 
Normandy ;  it  contains  less  coloring  matter,  whether  blue  or 
yellow,  than  the  pastel ;  its  durability  is  also  inferior  to  that 
of  the  last  named  substance.  M.  Chevreul  has  given  an  analy- 
sis of  the  pastel,  which  will  tend  to  throw  some  light  upon 
its  use. 

"When  the  leaves  are  subjected  to  the  action  of  the  press, 
we  obtain,  on  the  one  hand,  a  residue  of  a  ligneous  nature,  and, 
on  the  other,  a  juice  which  holds  in  suspension  sundry  matters 
which  give  it  a  cloudy  appearance.  Thrown  on  a  filter,  it 
leaves  a  greenish  matter  or  fecula,  which  is  formed  of  chloro- 
phylle,  wax,  indigo  blue,  and  an  azotized*  substance.  The 
clear  liquid,  after  passing  through  the  filter,  contains  an  azot- 
ized  substance  coagulable  by  heat;  an  azotized  substance  non- 
coagulable  by  heat;  a  red  matter,  resulting  from  the  union  of 
the  blue  coloring  principle  with  an  acid;  a  yellow  principle; 
gummy  matter;  some  liquid  sugar;  a  fixed  organic  acid;  free 
acetic  acid  and  acetate  of  ammonia;  the  odorous  principle  of 
the  cruciferae;  a  volatile  principle,  having  the  odor  of  osma- 
zome;  citrate  of  lime;  sulphates  of  lime  and  potash;  phosphates 
oflime;  magnesia,  iron,  and  manganese;  nitre,  and  chloride  of 
potassium. 

UM.  Chevreul  has  not  discovered  in  these  products  any  body 
possessed  of  the  power  of  seizing  upon  oxygen  in  an  energetic 
manner,  and  which  would  explain  the  action  of  the  pastel  in 
the  indigo  vat.  Still  we  cannot  doubt  that  the  principles  fur- 
nished by  this  matter  intervene,  to  a  certain  extent,  as  combus- 
tibles, and  that  we  must  refer  at  least  a  part  of  their  effect. to 
this  mode  of  action.  The  indigo  should  itself  be  selected  with 
care.  The  Guatimala  variety  is  preferred  for  the  urinary  or 
Indian  vat,  and  the  Bengal  indigo  for  the  pastel  vat. 

"Pastel  Yat. — The  first  care  of  the  dyer  in  preparing  the 
vat  should  be  to  furnish  the  bath  with  matters  capable  of  com- 
bining with  the  oxygen,  whether  directly  or  indirectly,  and  of 
giving  hydrogen  to  the  indigo.    We  must,  however,  be  careful 


*  Azote  is  a  synonyme  of  nitrogen. 


THE  PASTEL  VAT. 


295 


to  employ  those  substances  only  which  are  incapable  of  impart- 
ing to  the  bath  a  color  which  might  prove  injurious  to  the  in- 
digo. These  advantages  are  found  in  the  pastel,  the  woad,  and 
madder.  This  latter  substance  furnishes  a  violet  tint  when 
brought  into  contact  with  an  alkali,  and  by  the  addition  of  in- 
digo it  yields  a  still  deeper  sha^e. 

M  In  preparing  the  Indian  vat,  we  ordinarily  employ  one 
pound  of  fine  madder  to  two  pounds  of  indigo.  The  madder  is 
here  especially  useful,  by  reason  of  the  avidity  of  some  of  its 
principles  for  oxygen. 

"  The  pastel  vat,  when  prepared  on  a  large  scale,  ordinarily 
contains  from  18  to  22  lbs.  of  indigo;  11  lbs.  of  madder  would 
suffice  for  this  proportion,  but  we  must  also  bear  in  mind  the 
large  quantity  of  water  which  we  have  to  charge  with  oxidiza- 
ble  matters.  I  have  invariably  seen  the  best  results  from  em- 
ploying 22  lbs.  to  a  vat  of  this  size.  Bran  is  apt  to  excite  the 
lactic  fermentation  in  the  bath,  and  should  therefore  not  be 
employed  in  too  large  a  quantity;  7  to  9  lbs.  will  be  found 
amply  sufficient. 

"The  weld  is  rich  in  oxidizable  principles;  it  turns  sour, 
and  passes  into  the  putrid  fermentation  with  facility.  Some 
dyers  use  it  very  freely;  but  ordinarily  we  employ  in  this  bath 
an  equal  quantity  of  it  to  that  of  the  bran.  Sometimes  weld 
is  not  added  at  all. 

"In  most  dye-houses  the  pastel  is  pounded  before  introducing 
it  into  the  vat.  Some  practical  men,  however,  maintain  that 
this  operation  is  injurious,  and  that  it  interferes  with  its  dura- 
bility. This  is  an  opinion  which  deserves  attention.  The  effect 
of  the  pastel,  when  reduced  to  a  coarse  powder,  is  more  uniform ; 
but  this  state  of  division  must  render  its  alterations  more  rapid. 
When  the  bath  has  undergone  the  necessary  ebullition,  the 
pastel  should  be  introduced  into  the  vat,  the  liquor  decanted, 
and,  at  the  same  time,  7  or  8  lbs.  of  lime  added,  so  as  to  form 
an  alkaline  lye  which  shall  hold  the  indigo  in  solution.  Hav- 
ing well  stirred  the  vat,  it  should  be  set  aside  for  four  hours, 
so  that  the  little  pellets  shall  have  time  to  become  thoroughly 
soaked,  both  inside  and  out,  and  thus  be  prepared  for  fermen- 
tation. Some  think  coverings  are  to  be  spread  over  the  vat, 
so  as  to  preserve  it  from  contact  with  the  atmosphere.  After 
this  lapse  of  time,  it  is  to  be  again  stirred.  The  bath  at  this 
moment  presents  no  decided  character;  it  has  the  peculiar  odor 
of  the  vegetables  which  it  holds  in  digestion ;  its  color  is  of  a 
yellowish-brown. 

Ordinarily,  at  the  end  of  twenty-four  hours,  sometimes  even 
after  fifteen  or  sixteen,  the  fermentative  process  is  well  marked. 
The  odor  becomes  ammoniacal,  at  the  same  time  that  it  retains 


296 


INDIGO. 


the  peculiar  smell  of  the  pastel.  The  bath,  hitherto  of  a  brown 
color,  now  assumes  a  decided  yellowish-red  tint.  A  blue  froth, 
which  results  from  the  newly  liberated  indigo  of  the  pastel, 
floats  on  the  liquor  as  a  thick  scum,  being  composed  of  small 
blue  bubbles,  which  are  closely  agglomerated  together.  A 
brilliant  pellicle  covers  the  bath,  and  beneath  we  may  perceive 
some  blue  or  almost  black  veins,  owing  to  the  indigo  of  the 
pastel  which  rises  towards  the  surface.  If  the  liquor  be  now 
agitated  with  a  switch,  the  small  quantity  of  indigo  which  is 
evolved  floats  to  the  top  of  the  bath.  On  exposing  a  few  drops 
of  this  mixture  to  the  air,  the  golden  yellow  color  quickly  dis- 
appears, and  is  replaced  by  the  blue  tint  of  the  indigo.  This 
phenomenon  is  due  to  the  absorption  of  the  oxygen  of  the  air 
by  the  indigogen  from  the  pastel ;  in  this  state  we  might  even 
dye  wool  with  it  without  any  further  addition  of  indigo;  but 
the  colors  which  it  furnishes  are  devoid  of  brilliancy  and 
vivacity  of  tone,  at  the  same  time  that  the  bath  becomes 
quickly  exhausted. 

"The  signs  above  described  announce,  in  a  most  indubita- 
ble manner,  that  fermentation  is  established,  and  that  the  vat 
has  now  the  power  of  furnishing  to  the  indigo  the  hydrogen 
which  is  required  to  render  it  soluble — that  contained  in  the 
pastel  having  been  already  taken  up;  this,  then,  is  the  proper 
moment  for  adding  the  indigo,  which  should  be  previously 
ground  in  a  mill. 

"We  stated  above  that  the  liquor  of  the  vat  should  be  pre- 
viously charged  with  a  certain  quantity  of  lime;  we  also  find 
in  it  ammonia  generated  by  the  pastel;  but  a  part  of  these 
alkalies  become  saturated  by  the  carbonic  acid  gas  along  with 
the  proper  acids  of  the  madder  and  of  the  weld,  as  well  as  by 
the  lactic  acid  produced  by  the  bran  during  fermentation. 
The  ordinary  guide  of  the  dyer  is  the  odor,  which,  according 
to  circumstances,  becomes  more  or  less  ammoniacal.  The  vat 
is  said  to  be  either  soft  or  harsh ;  if  soft,  a  little  more  lime 
should  be  added  to  it.  The  fresh  vat  is  always  soft;  it  exhales 
a  feeble  ammoniacal  odor  accompanied  with  the  peculiar  smell 
of  the  pastel;  we  must,  therefore,  add  lime  to  it  along  with 
the  indigo;  we  usually  employ  from  five  to  six  pounds,  and, 
after  having  stirred  the  vat,  it  is  to  be  covered  over.  The 
indigo,  being  incapable  of  solution  except  by  its  combination 
with  hydrogen,  gives  no  sign  of  being  dissolved  until  it  has 
remained  a  certain  time  in  the  bath.  We  may  remark  that 
the  hard  indigoes,  as  those  of  Java,  require  at  least  eight  or 
nine  hours,  whilst  those  of  Bengal  do  not  need  more  than  six 
hours,  for  their  solution.  We  should  examine  the  vat  again 
three  hours  after  adding  the  indigo.    We  ordinarily  remark 


WOAD  VAT. 


297 


that  the  odor  is  by  this  time  weakened ;  we  must  now  add  a 
further  quantity  of  lime,  sometimes  less,  but  generally  about 
equal  in  amount  to  the  first  portion;  it  is  then  to  be  covered 
over  again,  and  set  aside  for  three  hours. 

u  After  this  lapse  of  time,  the  bath  will  be  found  covered 
with  an  abundant  froth  and  a  very  marked  copper-colored 
pellicle;  the  veins  which  float  upon  its  surface  are  larger  and 
more  marked  than  they  were  previously;  the  liquor  becomes 
of  a  deep  yellowish-red  color.  On  dipping  the  rake  into  the 
bath,  and  allowing  the  liquid  to  run  off  at  the  edge,  its  color, 
if  viewed  against  the  light,  is  of  a  strongly-marked  emerald- 
green,  which  gradually  disappears,  in  proportion  as  the  indigo 
absorbs  oxgen,  and  leaves  in  its  place  a  mere  drop  rendered 
opaque  by  the  blue  color  of  the  indigo.  The  odor  of  the  vat 
at  this  instant  is  strongly  ammoniacal;  we  also  find  in  it  the 
peculiar  scent  of  the  pastel.  When  we  discover  a  marked 
character  of  this  kind  in  the  newly-formed  vat,  we  may  with- 
out fear  plunge  in  the  stuff  intended  to  be  dyed  ;  but  the  tints 
given  during  the  first  working  of  the  vat  are  never  so  brilliant 
as  those  subsequently  formed ;  this  is  owing  to  the  yellow- 
coloring  matters  of  the  pastel,  which,  aided  by  the  heat,  become 
fixed  on  the  wool  at  the  same  time  as  the  indigo,  and  thus  give 
to  it  a  greenish  tint.  This  accident  is  common  both  with  the 
pastel  and  the  woad  vats ;  it  is,  however,  less  marked  in  the 
latter. 

"  When  the  stuff  or  cloth  has  been  immersed  for  an  hour  in 
the  vat  it  should  be  withdrawn;  it  would,  in  fact,  be  useless  to 
leave  it  there  for  a  longer  time,  inasmuch  as  it  could  absorb  no 
more  of  the  coloring  principle.  It  is,  therefore,  to  be  taken 
from  the  bath  and  hung  up  to  dry,  when  the  indigo,  by  attract- 
ing oxygen,  will  become  insoluble  and  acquire  a  blue  color. 
Then  we  may  replunge  the  stuff  in  the  vat,  and  the  shade  will 
immediately  assume  a  deeper  tint,  owing  to  renewed  absorption 
of  indigo  by  the  wool.  By  repeating  these  operations,  we  suc- 
ceed in  giving  very  deep  shades.  We  must  not,  however, 
imagine  that  the  cloth  seizes  only  on  that  portion  of  indigo 
contained  in  the  liquor  required  to  soak  it.  Far  from  such 
being  the  case,  experience  shows  that,  during  its  stay  in  the 
bath,  it  appropriates  to  itself,  within  certain  limits,  a  gradually 
increasing  quantity  of  indigo.  We  have  here,  then,  an  action 
of  affinity,  or  perhaps,  a  consequence  of  porosity  on  the  part 
of  the  wool  itself. 

"  Woad  Vat. — These  vats  are  extensively  employed  at  Lou- 
viers,  and  in  the  manufactories  of  the  north  of  France.  The 
bath  is  prepared  in  the  same  manner  as  in  the  foregoing  case; 
the  finely-cut  root  is  introduced  into  the  copper  along  with  2 


298 


INDIGO. 


lbs.  of  pounded  indigo,  9  lbs.  of  madder,  and  15 J  lbs.  of  slaked 
lime.  The  liquor  is,  after  the  necessary  ebullition,  poured 
upon  the  woad.  This  substance  contains  but  a  very  small 
quantity  of  coloring  principle ;  we  must,  therefore,  add  some 
indigo  when  preparing  the  vat,  so  as  to  indicate  the  precise 
instant  when  the  mixture  arrives  at  the  point  of  fermentation 
so  necessary  for  imparting  hydrogen  to  the  coloring  principle, 
and  for  rendering  it  soluble.  We  must  also  use  a  larger  quan- 
tity of  lime,  since  the  woad  contains  no  ammonia  resulting  from 
previous  decomposition,  such  as  we  find  to  be  the  case  with 
the  pastel  of  the  south.  When  the  vat  is  in  a  suitable  state  of 
fermentation,  a  rusty  color  becomes  manifest,  in  addition  to 
the  signs  already  described  in  speaking  of  the  pastel  vat;  be- 
sides the  ammoniacal  odor,  the  bath  always  retains  the  peculiar 
smell  of  the  woad.  The  pounded  indigo  is  now  added,  and  we 
proceed,  in  the  manner  already  detailed,  to  reduce  it  to  a  state 
of  solution  fit  for  dyeing. 

"  The  vats  prepared  by  means  of  pastel  have  greater  dura- 
bility than  those  made  with  the  woad ;  but  it  is  thought  that 
the  colors  given  by  the  latter  are  more  brilliant  than  those 
obtained  from  the  former  dye. 

"  Modified  Pastel  Vat. — This  vat  is  about  7  feet  in  depth, 
and  6|  feet  in  diameter.  It  is  made  of  copper,  and  heated  by 
steam.  The  lid  is  composed  of  three  segments,  each  of  which 
is  formed  of  two  planks,  about  an  inch  thick,  and  strongly 
secured  together  by  bolts. 

uThe  beating  is  performed  in  the  usual  way,  with  sticks, 
before  the  first  dipping,  after  having  moistened  the  cloth  in 
tepid  water.    This  operation  is  not  subsequently  repeated. 

"This  vat  is  prepared  with  13  lbs.  of  indigo,  17 J  lbs.  of 
madder,  4J  lbs.  of  bran,  9  lbs.  of  lime,  and  4J  lbs.  of  potash. 
Having  filled  the  vat,  we  heat  it  to  about  200°  Pah.,  and,  as 
soon  as  the  water  is  tepid,  introduce  441  lbs.  of  pastel.  The 
liquor  becomes  of  a  yellowish-brown  color;  small  bubbles  ap- 
pear upon  its  surface,  ordinarily  at  the  end  of  four  hours  if  the 
vat  be  heated  by  steam,  but  not  until  after  eight  or  twelve 
hours  where  heat  is  applied  by  the  common  fire ;  in  the  latter 
case  the  mixture  should  be  stirred  every  three  hours.  When 
the  liquor  displays  the  signs  of  fermentation,  we  add  the  above- 
mentioned  ingredients,  and  cover  the  vat  over ;  it  is  then  to 
be  set  aside,  stirring  it  every  three  hours,  or  oftener  if  the  fer- 
mentative action  be  very  rapid.  Each  time  that  it  is  stirred 
we  are  to  add  from  2  to  4  lbs.  of  lime;  if  fermentation  proceed 
quickly  we  even  use  more,  but  in  the  contrary  case  less.  After 
about  eighteen  hours,  we  plunge  into  the  vat  three  pieces  of 
common  cloth,  measuring  from  twenty  to  twenty-five  ells  in 


INDIAN  VAT. 


299 


length  each;  when  they  have  received  six  or  seven  turns,  they 
are  to  be  taken  out  again.  The  object  of  this  is  to  remove  the 
excess  of  lime  from  the  bath.  The  vat  is  then  set  aside  for 
three  hours,  when  it  is  to  be  stirred,  and  13  lbs.  of  indigo,  with 
2  lbs.  of  madder,  added  to  it.  We  now  again  apply  heat  to 
the  mixture. 

"  If  the  vat  contains  a  superabundance  of  lime,  it  will  be  un- 
necessary to  add  more ;  otherwise  we  throw  in  a  further  quan- 
tity. During  the  night  it  should  be  covered  with  a  cloth,  and 
a  workman  left  to  watch  it.  It  is  usually  stirred  once  before 
the  morning;  but  if  it  be  deficient  in  lime,  it  will  require  this 
manipulation  to  be  more  frequently  repeated,  and  also  fresh 
lime  added  to  it.  On  the  following  day  the  stirring  should  be 
continued  every  three  hours,  and  so  on  for  the  next  thirty 
hours,  taking  care  to  heat  the  vat  from  time  to  time.  On  the 
morning  of  the  fourth  day  the  dyeing  may  be  commenced. 

"The  temperature  should  be  maintained  at  a  pretty  uniform 
point;  if  it  be  too  hot,  the  blue  takes  a  red  reflection,  by  rea- 
son of  the  madder  contained  in  the  liquid.  A  vat  thus  pre- 
pared will  last  three  months;  we  may  even  work  it  for  double 
that  period,  but  after  the  third  month  it  appears  to  lose  some 
of  its  indigo. 

"We  maintain  the  power  of  the  vat  by  introducing  every 
night  2J  lbs.  of  madder.  Some  indigo  is  also  added  twice  or 
three  times  a  week.  These  additions  are  made  in  the  evening. 
After  the  former,  the  vat  is  left  at  rest  for  forty-two  hours ; 
with  the  latter  only  for  twenty-four,  at  the  same  time  observing 
the  precautions  already  indicated.  At  the  end  of  three  months, 
or  sooner  when  we  wish  to  stop  the  working  of  the  vat,  we 
exhaust  the  indigo ;  for  this  purpose  we  continue  to  charge  it 
every  night  for  the  space  of  a  month  with  madder,  and  dip 
into  it  white  cloths,  or  more  particularly  woollen  tissues,  which 
become  more  or  less  loaded  with  the  indigo.  We  must  con- 
tinue this  plan  until  these  matters  take  up  no  further  color. 
The  dippings  are  to  be  performed  twice  a-day  at  first,  but  once 
only  towards  the  termination.  Many  dyers  make  use  of  this 
bath  for  preparing  a  new  vat,  but  it  is  better  to  throw  this 
away  and  make  it  up  afresh  with  common  water. 

"Indian  Vat. — These  vats  are  of  more  simple  and  of  more 
ready  construction  than  the  pastel  or  woad  vats.  We  are  to 
boil  in  water  a  quantity  of  madder  and  of  bran,  proportioned 
to  the  weight  of  indigo  which  we  wish  to  employ.  After  two 
hours'  ebullition,  we  turn  into  this  bath  some  tartar-lees,  which 
are  also  to  be  boiled  for  an  hour  and  a-half  or  two  hours,  so  as 
to  charge  the  bath  with  whatever  soluble  matter  they  may 
contain  ;  after  this  ebullition  the  bath  should  be  allowed  to 


300 


INDIGO. 


cool,  and  the  indigo,  which  has  been  previously  ground,  is  then 
to  be  introduced.  Supposing  that  we  wish  to  employ  21  lbs. 
of  indigo,  the  following  would  be  the  proportions  used  in  pre- 
paring this  vat:  41  lbs.  of  tartar  lees,  13  lbs.  of  madder,  and 
5  lbs.  of  bran.  These  vats  are  usually  mounted  in  coppers  of 
a  conical  shape;  a  small  fire  should  be  kept  up  around  them, 
so  as  to  maintain  a  moderate  and  uniform  heat.  The  indigo 
will  usually  be  found  dissolved  at  the  end  of  twenty-four  hours, 
often  even  after  twelve  or  fifteen  hours.  The  liquor  has  a 
reddish  color  in  the  new  vats,  and  a  green  tint  in  those  which 
are  in  a  working  state.  The  frothy  surface,  as  well  as  the 
brilliant-colored  pellicle,  becomes  manifested  in  this  as  in  all 
other  preparations  of  a  like  kind. 

"This  species  of  vat  has  to  be  renewed  much  more  frequently 
than  the  woad  and  pastel  vats,  from  the  indigo  being  more  diffi- 
cult to  dissolve  after  a  certain  lapse  of  time.  A  moderate  heat 
should  be  maintained  in  all  these  vats. 

"Potash  Vat. — This  species  of  vat  is  extensively  employed 
at  Elbeuf  for  the  dyeing  of  wool  in  the  flock.  It  presents  in 
all  respects  a  perfect  analogy  with  the  Indian  vat ;  in  fact,  the 
action  of  the  tartar-lee  in  the  latter  preparation  depends  entirely 
on  the  carbonate  of  potash  which  it  contains.  The  ingredients 
used  in  the  preparation  of  the  potash  vat  are — bran,  madder, 
and  the  subcarbonate  of  potash  of  commerce. 

"We  obtain  the  deep  shades  in  this  species  of  vat  with 
greater  celerity  than  in  all  others,  a  fact  which  undoubtedly 
depends  on  the  greater  power  which  potash  has  of  dissolving 
indigo  than  is  possessed  by  lime.  Experience  proves  that  the 
potash  vat  has  the  advantage  in  point  of  celerity  of  nearly  a 
third  ;  but  this  is  balanced  by  the  inconvenience  resulting  from 
the  darker  shade,  which  we  must  attribute  to  the  large  quantity 
of  coloring  matter  of  the  madder  dissolved  by  the  alkaline  lee, 
and  which  becomes  fixed  on  the  stuff  with  the  indigo. 

"To  render  this  vat  in  its  most  favorable  state,  the  indigo 
should  be  made  to  undergo  a  commencement  of  hydrogenation 
before  turning  it  into  the  mixture ;  for  this  purpose  we  prepare 
in  a  small  copper  a  bath  analogous  to  that  in  the  vat,  to  which 
the  pounded  indigo  is  added.  This  bath  is  maintained  for 
twenty-four  hours  at  a  moderate  heat,  taking  care  to  stir  it 
from  time  to  time.  The  indigo  assumes  a  yellowish  color,  be- 
comes dissolved,  and  in  this  state  is  turned  into  the  vat ;  we 
thus  avoid  many  delays  and  losses  in  its  preparation,  and,  in- 
deed, it  would  be  desirable  if  a  similar  plan  were  adopted  with 
all  these  compounds. 

"German  Vat. — This  vat  is  of  nearly  similar  dimensions  to 
that  used  for  the  woad,  being  three  times  the  size  of  the  potash 


GERMAN  VAT. 


301 


vat.  Its  diameter  is  about  6|  feet,  and  its  depth  8 J  feet. 
Having  filled  the  copper  with  water,  we  are  to  heat  it  to  200° 
Fah.;  we  then  add  20  pailsful  of  bran,  22  lbs.  of  carbonate  of 
soda,  11  lbs.  of  indigo,  and  5J  pounds  of  lime,  thoroughly 
slaked,  in  powder.  The  mixture  is  to  be  well  stirred,  and  then 
set  aside  for  two  hours;  the  workman  should  continually  watch 
the  progress  of  the  fermentation,  moderating  it  more  or  less 
by  means  of  lime  or  carbonate  of  soda,  so  as  to  render  the  vat 
in  a  working  state  at  the  end  of  twelve,  fifteen,  or,  at  the  most, 
eighteen  hours.  The  odor  is  the  only  criterion  by  which  the 
workman  is  enabled  to  judge  of  the  good  state  of  the  vat,  he 
must  therefore  possess  considerable  tact  and  experience. 

"  In  the  process  of  dipping  we  introduce  84  lbs.,  106  lbs., 
or  even  130  lbs.  of  wool,  in  a  net  bag,  similar  to  that  used  in 
the  woad  vat,  taking  care  that  the  bag  is  not  allowed  to  rest 
against  the  sides  of  the  copper.  When  the  wool  has  sufficiently 
imbibed  the  color,  we  remove  the  bag  containing  it,  and  allow 
it  to  drain  for  a  short  time  over  the  vessel.  We  operate  in  this 
way  on  two  or  three  quantities  in  succession ;  we  then  remove 
the  vat,  and  set  it  aside  for  two  hours  ;  we  must  be  careful, 
from  time  to  time,  to  replace  the  indigo  absorbed  by  the  wool, 
as  also  to  add  fresh  quantities  of  bran,  lime,  and  crystallized 
carbonate  of  soda,  so  as  constantly  to  maintain  the  fermentation 
at  a  suitable  point. 

"  The  German  vat  differs,  then,  from  the  potash  vat  by  the 
fact  that  the  potash  is  replaced  by  crystallized  carbonate  of 
soda  and  caustic  lime,  which  latter  substance  also  gives  to  the 
carbonate  of  soda  a  caustic  character.  It  presents  a  remark- 
able saving  as  compared  to  the  potash  vat ;  hence  the  frequency 
of  its  employment ;  but  it  requires  great  care,  and  is  more 
difficult  to  manage.  It  also  offers  considerable  economy  of 
labor;  one  man  is  amply  sufficient  for  each  vat. 

uThe  army  cloth  is  usually  dyed  by  means  of  the  pastel  vat, 
which  gives  the  most  advantageous  results.  We  here  make 
use  of  vats  about  8  J  feet  in  depth,  and  5  feet  in  diameter,  into 
which  we  introduce  from  361  lbs.  to  405  lbs.  of  pastel  or  of 
woad,  after  previous  maceration.  The  vat  is  to  be  filled  with 
boiling  water,  and  we  then  add  to  the  bath  22  lbs.  of  madder, 
17^  lbs.  of  weld,  and  13  lbs.  of  bran.  The  mixture  is  to  be  main- 
tained in  a  state  of  ebullition  for  about  half  an  hour;  we  next 
add  a  few  pailsful  of  cold  water,  taking  care,  however,  not  to 
lower  the  temperature  beyond  130°  Fah.;  during  the  whole  of 
this  time  a  workman,  provided  with  a  rake,  keeps  incessantly 
stirring  the  materials  of  the  bath.  The  vat  is  then  accurately 
closed  by  means  of  a  wooden  lid,  and  surrounded  by  blankets, 
so  as  to  keep  up  the  heat.    It  is  now  put  aside  for  six  hours  ; 


302 


INDIGO. 


after  this  time  it  is  again  stirred  by  means  of  a  rake,  for  the 
space  of  half  an  hour  ;  and  this  operation  should  be  repeated 
every  three  hours  until  the  surface  of  the  bath  becomes  marked 
with  blue  veins;  we  then  add  from  six  to  eight  pounds  of 
slaked  lime. 

"  The  color  of  the  vat  now  borders  on  a  blackish-blue.  We 
immediately  add  the  indigo  in  a  quantity  proportioned  to 
the  shade  which  we  wish  to  obtain.  The  pastel  in  the  fore- 
going mixture  may  last  for  several  months  ;  but  we  must  renew 
the  indigo  in  proportion  as  it  becomes  exhausted,  at  the  same 
time  adding  both  bran  and  madder.    In  general  we  employ — 

"  11  to  13  lbs.  of  good  indigo  for  100  lbs.  of  fine  wool. 

"9  to  11  lbs.  of  good  indigo  for  100  lbs.  of  common  wool. 

u9  to  11  lbs.  of  good  indigo  for  131  yards  of  cloth  dyed  in 
the  piece. 

"Management  of  the  Vats. — A  good  condition  of  the  vat 
is  recognized  by  the  following  characters  :  The  tint  of  the  bath 
is  of  a  fine  golden-yellow,  and  its  surface  is  covered  with  a 
bluish  froth  and  a  copper  colored  pellicle.  On  dipping  the  rake 
into  the  bath,  there  escape  bubbles  of  air,  which  should  burst 
very  slowly;  when  they  vanish  quickly,  it  becomes  an  indica- 
tion that  we  must  add  more  lime.  The  paste  which  is  found 
at  the  bottom  of  the  vat,  green  at  the  moment  of  its  being 
drawn  up,  should  become  brown  in  the  air  ;  if,  however,  it  re- 
mains green,  this  is  a  further  sign  that  more  lime  is  required. 
Lastly,  the  vat  should  exhale  the  odor  of  indigo.  We  usually 
complete  the  assurance  of  the  vat  being  in  a  good  state  by 
plunging  into  it,  after  two  hours'  respite,  a  skein  of  wool,  which, 
on  being  withdrawn  after  the  lapse  of  half  an  hour,  should 
present  a  green  color,  but  change  directly  to  blue.  We  then 
once  more  mix  the  materials  of  the  vat,  and  two  hours  after,  it 
may  be  considered  ready  for  dyeing. 

"These  vats,  like  those  already  described,  are  provided  with 
a  large  wooden  ring,  the  interior  of  which  is  armed  with  a  kind 
of  network,  for  the  purpose  of  preventing  the  objects  which  are 
intended  to  be  dyed  coming  in  contact  with  the  materials  at  the 
bottom  of  the  vat;  we,  moreover,  take  the  precaution  of  in- 
closing the  wool  or  cloth  in  bags.  These  tissues,  when  plunged 
into  the  bath,  should  remain  there  for  a  longer  or  shorter  time, 
according  to  the  shade  which  we  wish  to  obtain;  one  dipping, 
however,  will  never  suffice  for  this  object;  usually  we  leave  in 
the  stuff  for  half  an  hour  only  ;  it  is  then  to  be  taken  from  the 
bath,  wrung,  and  exposed  to  the  air.  This  operation  is  repeated 
until  we  have  succeeded  in  procuring  the  desired  shade ;  we 
ordinarily  suffer  three  hours  to  elapse  between  each  dipping. 
The  heat  ot  the  vat  should  never  be  allowed  to  fall  below  130° 


MANAGEMENT  OF  THE  VATS. 


303 


Fah.  After  each  operation  the  bath  must  be  well  stirred,  and 
fresh  lime  added  ;  generally  speaking,  a  pound  a  day  will 
suffice.  We  re-establish  the  indigo  about  every  second  day. 
When  once  this  vat  is  well  mounted,  and  we  are  careful  to 
examine  its  working,  we  may  dye  from  two  to  four  batches  a 
day  with  it. 

"  When  the  stuffs  have  acquired  the  desired  shade,  they  are 
first  to  be  washed  in  common  water,  and  then  in  a  very  weak 
solution  of  hydrochloric  acid  (about  one  part  in  a  thousand)  ; 
after  this  they  are  again  rinsed  in  pure  water. 

uThe  Indian  vat  is  much  more  easily  managed  than  the  fore- 
going; it  presents  less  danger  of  failure,  from  the  fact  that  it  is 
quickly  exhausted,  and  also  from  the  fermentative  process,  which 
is  so  difficult  to  govern  in  the  pastel  vat ;  this  vat  not  having 
time  to  change  in  character.  It  is  prepared  by  first  introducing 
an  equal  quantity  of  madder  and  of  bran,  and  a  triple  quantity 
of  potash  ;  this  is  to  be  gradually  heated  until  it  reaches  a 
temperature  of  167°  Fah.,  and  we  then  add  to  it  the  indigo, 
thoroughly  agitating  the  matters  for  half  an  hour.  The  vat  is 
maintained  at  a  temperature  of  86°  to  100°  Fah.,  by  keeping 
it  closely  covered,  and  at  the  same  time  the  mixture  is  to  be 
stirred  occasionally  at  intervals  of  twelve  hours.  It  should  by 
this  time  present  a  beautiful  green  shade,  the  liquor  being  sur- 
mounted by  a  copper-colored  pellicle  and  a  purplish  froth.  We 
may  now  commence  the  dyeing,  following  the  same  course 
as  with  the  pastel  vat;  but  the  stirrings  being  here  repeated 
much  more  frequently  than  with  the  other  mixture,  we  can  dye 
a  larger  quantity  of  wool  within  a  given  time.  When  the  vat 
ceases  to  give  a  brilliant  blue,  we  must  altogether  renew  it;  if 
it  be  merely  weakened,  we  add  to  it  a  small  quantity  of  freshly- 
prepared  liquor  containing  a  few  pounds  of  potash,  and  a  little 
less  bran  and  madder.  In  giving  the  dark  and  the  clear  sky- 
blues,  we  must  be  careful  to  employ  a  quantity  of  indigo  pro- 
portioned to  the  color  which  we  wish  to  obtain,  or,  better  still, 
we  may  use  the  previously  exhausted  vat  for  the  dark  blue. 

"When  exposed  to  the  influence  of  the  putrid  fermentation, 
indigo  is  decomposed  and  loses  its  color.  If  rendered  soluble, 
it  obeys  the  impulse  communicated  to  theazotized  matters  with 
which  it  is  brought  into  contact,  although,  if  macerated  in  pure 
water  at  the  ordinary  temperature,  it  is  itself  decomposed  with 
great  difficulty. 

"  The  pastel  and  the  woad  are  very  prone  to  the  putrid  fer- 
mentation, by  reason  of  the  large  quantity  of  azotized  matters 
which  they  contain,  as  do  all  the  cruciferae ;  they  require, 
therefore,  considerable  care  in  their  employment. 

"  When  a  vat  is  mounted,  if  the  fermentation  be  allowed  to 


304 


INDIGO. 


continue  unchecked,  after  the  appearance  of  the  blue  froth  and 
the  other  signs  already  indicated,  the  liquor  will  acquire  a  yel- 
low color  similar  to  that  of  beer;  the  froth  will  become  white; 
it  will  give  out  a  stale  smell  and  lose  its  ammoniacal  odor  ;  after 
a  few  days  it  will  turn  whitish,  and  exhale  a  smell  at  first  simi- 
lar to  that  of  putrefied  animal  substances;  then  it  will  acquire 
the  odor  of  rotten  eggs,  and  set  free  sulphureted  hydrogen. 
The  lime  in  the  pastel  and  the  woad  vats,  and  the  tartar-lee 
and  potash  in  the  other  mixtures,  are  used  for  the  purpose  of 
preventing  these  accidents. 

"  Besides  the  oxygenated  compound,  which  is  formed  by 
the  combinaiion  of  oxygen  with  the  extractive  matters  of  the 
plants  held  in  digestion,  there  is  a  production  of  carbonic  acid 
which  saturates  the  alkaline  lee,  and  forms  a  carbonate  of  lime 
in  the  pastel  vat.  We  find  this  attached  to  the  sides  of  the 
vat  in  such  quantity,  that  the  inside  of  these  vessels  becomes 
incrusted  with  it  to  a  considerable  depth.  It  is  this  product 
which  dyers  call  the  tartar  of  the  vat;  it  effervesces  with  acids, 
and  gives  on  analysis  carbonic  acid,  lime,  and  a  few  particles 
of  indigo.  In  the  potash  vat  the  solubility  of  the  carbonate 
of  potash  prevents  its  deposition;  but  it  is  very  probable  that 
we  have  even  here  a  formation  of  some  carbonated  products, 
perhaps  in  part  formed  at  the  expense  of  the  carbonic  acid  of 
the  air. 

"The  soluble  extractive  principle  being  the  only  matter 
which  remains  in  solution  in  the  bath  with  the  indigo,  the 
lime,  &c.,  we  have  formed  deposits  which,  varying  both  in  their 
volume  and  in  the  greater  or  less  facility  with  which  they  are 
precipitated  during  the  various  periods  of  fermentation,  lead  to 
a  more  or  less  considerable  waste  of  time.  If  we  plunge  a 
piece  of  woollen  tissue  into  a  vat  which  has  been  recently 
stirred,  it  will  acquire  a  dark  color,  and  will  be  found  covered 
with  brown  stains  which  are  with  difficulty  removed.  When 
the  woad  or  paste  vat  has  been  stirred,  it  need  be  left  two  or 
three  hours  only  before  plunging  in  the  stuff,  at  least  during 
the  early  months  of  its  working,  inasmuch  as  the  pastel,  being 
but  slightly  divided  and  attenuated,  is  readily  precipitated;  but 
when,  by  reason  of  its  extreme  division,  in  consequence  of 
repeated  operations,  it  is  thrown  down  with  less  facility,  the 
dipping  should  not  be  performed  oftener  than  three  times  in  the 
day. 

"The  Indian  vat  requires  less  time  than  the  others;  we  may 
even  dye  with  it  an  hour  after  stirring  the  mixture.  The 
potash,  being  soluble,  forms  no  precipitate;  while  the  ligneous 
fibre  of  the  madder  and  the  pellicles  of  the  bran  become  de- 


INDIGO. 


305 


posited  with  great  facility.  We  can  also  dip  with  these  vats 
much  oftener  than  with  those  made  by  pastel  or  woad." 

We  here  give  three  compositions  for  the  copperas  vat: — 

Dark  Blue.    Medium.    Light  Blue. 

Water  (buckets),  600  600  600 

Caustic  lime  (lbs.),  88  83  13.5 

Copperas  (lbs.),  77  22  5.0 

Ground  indigo  (lbs.)  33  11  2.2 

Soda  ash  (lbs.),  2.2 

Receipts  and  formulas  require  in  their  application  not  only 
that  the  figures  should  be  followed,  but  also  that  the  quality  of 
the  ingredients  should  not  vary  too  much.  The  want  of  suc- 
cess in  many  indigo  vats  is  often  caused  by  employing  poor 
materials,  too  far  from  a  good  average.  Indigo  is  a  substance 
which  contains  from  35  to  75  per  cent,  of  true  indigo.  With 
such  a  wide  range,  analyzing  indigo  by  sight  only,  may  lead  to 
incorrect  results,  and  great  trouble  in  the  management  of  the 
vats. 

If  the  indigo  is  too  poor,  and  the  regular  proportion  of  lime 
and  copperas  is  added,  the  protoxide  of  iron  will  swim  if  it 
does  not  precipitate  part  of  the  indigo,  which  is  probable,  when 
we  consider  that  the  deposit  of  the  vats  often  contains  a  com- 
pound of  iron  and  indigo.  Lime  is  to  be  considered  also; 
American  limes  are  always  mixed  with  more  or  less  magnesia. 
The  sulphate  of  lime  formed  goes  to  the  bottom,  but  the  sul- 
phate of  magnesia  is  very  soluble;  and  by  successive  additions 
of  magnesia  and  lime,  the  specific  gravity  of  the  liquid  may  be 
increased  to  a  point  when  the  insoluble  substances  will  have 
difficulty  to  reach  the  bottom,  and  hence  they  will  swim.  It 
would  be  better  to  employ  limes  free  from  magnesia.  White 
marble  lime,  and  especially  oyster  lime,  do  not  contain  mag- 
nesia. 

Copperas  suspected  of  having  in  it  too  much  peroxide  can  be 
transformed  into  sulphate  of  protoxide  by  boiling  it  in  a  vessel 
lined  with  lead,  with  clean  iron  scraps  or  turnings.  A  small 
addition  of  oil  of  vitriol,  if  the  copperas  is  not  already  very 
acid,  will  help  the  transformation.  After  boiling,  if  the  solu- 
tion is  not  immediately  used,  it  should  be  covered  with  boards. 

Carmine  of  indigo  has  been  recently  manufactured  with  a 
refined  indigo,  treated  by  strong  muriatic  acid,  which  dissolves 
the  lime,  iron,  and  amylaceous  substances  ;  and  subsequently  by 
a  weak  solution  of  caustic  soda,  which  dissolves  other  organic 
impurities.  The  result  is  a  great  brilliancy  of  shades. 
20 


306 


LOGWOOD. 


Logwood. 

Logwood  is  the  Boisde  Campeche  and  Boisbleu  of  the  French, 
and  the  Blavhoh  of  the  German  dyers.  This  wood  is  brought 
to  us  from  Jamaica  and  from  the  eastern  shores  of  the  Bay  of 
Campeachy;  on  this  account  it  is  distinguished  in  commerce 
by  the  names  of  Campeachy  and  Jamaica  logwood.  The  former 
is  considered  much  superior  to  the  latter,  and  brings  always  a 
higher  price  in  the  market.  Among  botanists,  the  logwood 
tree  is  known  by  the  name  of  Hcematoxylon  Campechiacum.  In 
a  favorable  soil  it  grows  to  a  very  great  size ;  its  bark  is  thin 
and  smooth,  but  furnished  with  thorns ;  its  leaves  resemble 
the  laurel;  the  wood  is  hard,  compact,  and  capable  of  taking 
a  fine  polish  ;  its  specific  gravity  is  much  higher  than  water,  in 
which  it  consequently  sinks. 

We  are  not  aware  who  first  introduced  logwood  as  a  dyeing 
agent;  but  its  nature,  and  the  art  of  using  it  as  such,  seem  to 
have  been  but  little  understood  in  the  reign  of  Queen  Eliza- 
beth; for  we  find  her  government  issuing  an  enactment  entirely 
forbidding  its  use.  The  document  is  curious,  and  affords  a 
good  proof  of  the  absurdity  of  a  government  interfering  with 
the  industry  of  its  subjects.  The  act  is  entitled  "An  Act  for 
the  abolishing  of  certeine  deceitful  stuffe  used  in  dyeing  of 
clothes and  it  goes  on  to  state  that,  "Whereas  there  hath 
been  brought  from  beyond  the  seas  a  certeine  kind  of  stuffe 
called  logwood,  alias  blockwood,  wherewith  divers  dyers,"  &c, 
and  "Whereas  the  clothes  therewith  dyed,  are  not  only  solde 
and  uttered  to  the  great  deceyte  of  the  Queene's  loving  sub- 
jects, but  beyond  the  seas,  to  the  great  discredit  and  sclaunder 
of  the  dyers  of  this  realme.  For  reformation  whereof,  be  it 
enacted  by  the  Queene  our  Soveraygne  Ladie,  that  all  such  log- 
wood, in  whoes  handes  soever  founde,  shall  be  openly  burned 
by  authoritie  of  the  maior."*  This  act  was  put  forth  in  the 
23d  year  of  the  Queen's  reign,  and  was  renewed  again  in  the 
39th,  with  the  addition  that  the  person  so  offending  was  liable 
to  imprisonment  and  the  pillory.  Upwards  of  eighty  years 
elapsed  before  the  real  virtues  of  this  dyeing  agent  were  ac- 
knowledged;  and  there  is  no  dyewood  we  know  now  so  uni- 
versally used,  and  so  universally  useful. 

Like  many  other  valuable  substances,  logwood  was  long  used 
before  anything  was  known  of  the  real  nature  of  the  coloring 
principle.  Chevreul  made  a  chemical  examination  of  the  wood, 
and  found  it  to  contain  a  distinct  coloring  substance,  which  he 
called  hasmatine,  a  name  which  has  since  been  changed  to  haema- 

*  Parkes,  Chemical  Essays,  8vo.  vol.  i.  page  632. 


COLORING  MATTERS. 


307 


toxylin,to  avoid  any  confusion  with  a  substance  having  a  simi- 
lar name,  contained  in  blood.  Logwood  contains,  besides  this 
coloring  matter,  resin  and  oil,  acetic  acid,  and  a  double  salt  of 
potash  and  lime,  with  a  vegetable  acid.  It  sometimes  contains 
also  sulphate  of  lime,  a  little  alumina,  peroxide  of  iron,  and 
oxide  of  manganese.  These  ingredients,  however,  vary;  some 
woods  having  more  than  others,  and  others  wanting  some  of 
them  altogether.  These  varieties  of  constitution  probably 
arise  from  the  varying  qualities  of  the  soil  on  which  the  wood 
is  grown. 

We  have  frequently  tried  pieces  of  logwood  as  imported,  and 
the  average  ash  left  after  burning  was  1.5  per  cent.,  half  of 
which  was  lime,  with  a  trace  of  iron,  and  the  remainder  con- 
sisted of  magnesia,  alumina,  and  silica. 

Chevreul's  process  for  procuring  the  coloring  matter  is  by 
subjecting  logwood,  after  grinding,  to  digestion  for  a  few  hours 
in  water  at  120°  or  130°  Fah.,  afterwards  filtering  the  liquor 
and  evaporating  to  dryness  ;  what  remains  is  put  into  strong 
alcohol  for  a  day;  this  is  again  filtered,  and  the  clear  liquor 
evaporated  till  it  becomes  thick  ;  to  this  is  added  a  little  water, 
and  evaporated  anew ;  it  is  then  left  to  itself,  and  the  coloring 
matter  crystallizes. 

An  improvement  on  this  method  has  been  recommended  by 
Erdmann.  The  extract  of  logwood  being  evaporated  to  dry- 
ness, is  pulverized,  and  mixed  with  a  considerable  quantity  of 
pure  silicious  sand,  to  prevent  the  agglutination  of  the  extract, 
and  the  whole  allowed  to  stand  several  days  with  five  or  six 
times  its  volume  of  ether  ;.  the  mixture  being  often  shaken,  the 
clear  solution  is  poured  off  and  distilled,  until  there  is  only  a 
small  syrupy  residue.  By  this  means  most  of  the  ether  is  saved  ; 
and  this  residue  being  mixed  with  a  certain  quantity  of  water, 
is  allowed  to  stand  for  some  days,  when  the  hematoxylin  crys- 
tallizes out,  and  may  be  dried  between  folds  of  blotting  paper. 

We  are  afraid  both  of  these  processes  will  be  too  tedious  for 
adoption  in  a  dye-house.  We  have  seen  some  very  good  speci- 
mens of  the  hsematoxylin  obtained  by  evaporating  a  strong 
decoction  of  logwood  nearly  to  dryness,  and  allowing  it  to 
stand  for  several  days;  a  solid  matter  settles  to  the  bottom, 
having  a  syrupy  fluid  above  it;  large  crystals  of  hematoxylin 
appear  to  grow  from  the  crust,  giving  it,  when  removed,  a 
most  beautiful  velvety  appearance.  The  crystals  vary  in  length 
from  one-fourth  to  five-eighths  of  an  inch.  They  dissolve  rea- 
dily in  hot  water,  but  very  slowly  in  cold  ;  they  are  also  soluble 
in  alcohol.  When  dissolved  in  distilled  water,  the  solution  has 
a  beautiful  rich  wine  color  ;  but  when  the  least  trace  of  lime  or 


308 


LOGWOOD. 


iron  is  present  in  the  water  (and  very  few  waters  are  free  from 
these),  its  color  is  materially  altered.  The  action  of  reagents 
is  very  powerful.  Potash,  when  first  put  in,  colors  the  solution 
violet ;  but  this  speedily  passes  into  a  purple,  becoming  brown- 
ish-yellow; and,  in  a  little  time,  the  mixture  becomes  almost 
colorless.  The  reason  of  this  final  change  is,  that  a  quantity  of 
oxygen  is  absorbed;  the  hematoxylin  is  thereby  destroyed, 
and  the  caustic  alkali  converted  into  a  carbonate  from  the  de- 
composition of  the  coloring  matter.  Caustic  soda  has  a  similar 
effect;  but  the  carbonate  of  soda  is  much  more  mild  in  its 
action  than  carbonate  of  potash. 

An  extract  of  logwood  is  sold  in  France  in  a  crystalline  form, 
and  is  obtained  from  a  decoction  of  the  wood.  The  crystals 
are  dark-red,  nearly  black;  it  is  hematoxylin,  with  several  im- 
purities, but  yields  a  very  considerable  quantity  of  color. 

The  action  of  ammonia  on  hematoxylin  is  similar  to  that  of 
potash  and  soda,  but  much  more  powerful  in  regard  to  its 
changing  color,  and  less  destructive  upon  the  substance.  Some 
beautiful  and  also  amusing  experiments  may  be  performed 
with  ammonia  and  the  coloring  matter  of  logwood.  If  a  jar 
full  of  distilled  water  be  taken,  and  a  few  drops  of  a  solution 
of  hematoxylin  be  added,  not  so  much  as  to  give  a  perceptible 
coloring  to  the  water;  on  adding  a  few  drops  of  ammonia,  the 
water  instantly  takes  a  reddish  tint,  and  changes  so  rapidly, 
that  in  two  minutes,  if  the  jar  is  large,  the  color  is  so  dark  a 
violet  shade  that  the  light  can  hardly  be  transmitted  ;  in  a 
little  it  becomes  redder,  and  gradually  passes  away.  This  ex- 
periment may  be  repeated  by  placing  the  jar  simply  in  the 
fumes  of  ammonia  ;  the  water  begins  to  color  at  the  top,  and, 
as  the  absorption  goes  on,  the  color  passes  gradually  down,  so 
that  when  it  is  dark  at  the  top,  it  is  slightly  tinged  at  the  bot- 
tom, and  so  on  till  the  whole  is  converted  into  a  dark  violet, 
seemingly  by  magic. 

Erdmann  has  been  able  to  collect  this  compound  of  hema- 
toxylin and  ammonia,  and  finds  that  the  coloring  matter  ab- 
sorbs three  equivalents  of  oxygen  under  the  influence  of  the 
ammonia,  and  is  converted  into  a  substance  which  he  names 
hwmatein.  This  hematein  combines  with  ammonia,  and  forms  a 
violet-black  powder,  which  is  soluble  in  water,  giving  it  an 
intense  purple  color,  which  spontaneously  fades,  and  passes 
away  by  keeping. 

The  action  of  alkalies  upon  logwood  is  similar  to  those  de- 
scribed upon  its  coloring  matter,  and  suggests  the  cause  why 
those  who  add  a  little  alkali  to  their  logwood  liquor  while  dye- 
ing black,  on  purpose  to  give  the  color  of  the  logwood  a  rich- 
ness, and  prevent  the  action  of  the  iron  upon  it,  invariably 


COLORING  MATTERS. 


309 


have  a  bad  grayish-black.  Stale  urine,  indeed,  which  is  most 
generally  used  for  this  purpose,  if  not  used  cautiously,  pro- 
duces the  same  bad  color  from  the  ammonia  which  it  contains. 
For  this  reason,  also,  we  always  wash  off  the  lime,  when  it  is 
used  to  pass  the  cloth  through  it  after  being  impregnated  with 
iron,  otherwise  the  lime  on  the  cloth  causes  the  coloring  mat- 
ter to  undergo  similar  changes  with  the  other  alkaline  sub- 
stances, and  gives  the  blacks  thus  dyed  a  grayish  appearance. 
Indeed,  so  delicate  is  the  action  of  all  earthy  and  alkaline  salts 
upon  logwood,  that  it  has  been  proposed  as  a  test  for  the  pre- 
sence of  lime  in  water. 

In  the  chemical  investigation  of  logwood,  the  coloring  mat- 
ter has  been  obtained  in  two  conditions,  differing  in  chemical 
composition  only  in  one  having  more  water  than  the  other; 
but  these  researches  have  led  to  some  curious  and  interesting 
speculations  upon  the  relation  which  it  has  to  other  blue  color- 
ing matters  of  vegetables,  particularly  those  of  indigo  and 
orceine  (the  coloring  matter  of  archil).  There  is,  however, 
this  difference,  that  hematoxylin  has  no  nitrogen,  the  others 
have;  but  instead  of  nitrogen  it  has  water.  Their  compara- 
tive compositions  are  as  follows: — 

Orceine 
Indigo  blue . 
Indigo  white 

Protohydrate  hematoxylin 
Perhydrate  heematoxylin 

These  analogies,  in  connection  with  the  relations  of  color, 
are  striking;  and  if  we  could,  by  some  transformation,  obtain 
in  the  other  two  matters  the  permanence  of  indigo,  the  acqui- 
sition would  be  highly  worthy  of  attention. 

The  action  of  metallic  oxides  upon  the  coloring  matter  of 
logwood  is  somewhat  similar  to  the  action  of  these  oxides  on 
logwood  itself,  varying  considerably  with  the  dissolving  men- 
strua of  the  oxide,  and  the  particular  state  of  oxidization. 

Pjotosalts  of  iron  give  Blue-black  precipitates,  permanent. 
Persalts  of  iron  Jet-black   precipitates,   which  be- 
come brown. 

Protosalts  of  tin  Kich  wine-color  precipitates,  per- 
manent. 

Persalts  of  tin  Deep  wine-color  precipitates,  which 

•  become  brown. 

Acetate  of  lead  Brownish-black  precipitate,  which 

passes  to  gray. 

Acetate  of  copper  .  .  .  Greenish-black,  passing  to  brown. 
Salts  of  alumina  ....  Wine-color  precipitates,  permanent. 


c. 

H. 

0. 

N. 

Water, 

32 

18 

7 

2 

32 

10 

4 

2 

32 

10 

2 

2 

2 

32 

14 

i  6 

0 

1 

32 

14 

6 

0 

3 

310 


LOGWOOD. 


These  are  the  principal  metallic  salts  used  with  logwood, 
and  their  effects.  The  acid  in  which  the  oxides  are  dissolved 
affects  materially  the  results  obtained;  the  iron  is  used  in  the 
state  of  sulphate  or  acetate;  the  tin  as  chloride,  with  free  acid  ; 
lead  and  copper  as  acetates.  The  protosalts  give,  with  log- 
wood, the  most  brilliant,  and  also  the  most  permanent  colors; 
this  should  be  constantly  attended  to.  The  iron  protosalts,  if 
exposed  to  the  air,  pass  very  readily  into  the  state  of  persalts, 
especially  if  the  salts  be  neutral — that  is,  have  no  more  acid 
than  is  combined  with  the  oxide.  A  little  free  acid  prevents 
this  change,  but  generally  produces  bad  effects  upon  logwood. 
However,  where  the  use  of  a  protosalt  of  iron  is  necessary,  any 
persalt  in  the  mordant  may  be  reduced  to  the  proto-state  by 
the  immersion  in  it  of  a  piece  of  clean  iron,  a  few  hours  pre- 
vious to  using  the  solution.  When  an  iron  salt  becomes  peroxi- 
dized  by  exposure  to  the  air,  every  third  atom  is  precipitated 
as  an  insoluble  oxide — the  acid  leaving  this  atom,  and  com- 
bining with  two  atoms  iron,  and  three  oxygen,  to  form  a  per- 
salt (page  154).  When  a  piece  of  iron  is  put  into  a  persalt 
solution,  the  following  reaction  takes  place: — 


Persalt  of  iron  composed 


Iron  .Protosalt, 


Iron ....  -^^^protosalt. 

Oxygen- 
Oxygen- 
Oxygens 
Acid.. 
Acid.. 
Acid.. 

Piece  of  clean  iron    ^Protosalt. 

This  operation  ought  to  be  performed  just  previous  to  using 
the  solution,  which  should  be  as  little  exposed  as  possible;  for 
when  the  salt  is  all  converted  into  the  proto-state;  the  atmo- 
sphere again  speedily  destroys  it. 

Decoctions  of  logwood  are  prepared  in  the  dye-house  either 
by  boiling  or  by  scalding ;  if  the  logwood  is  chipped  or  cut, 
it  requires  to  be  boiled  for  two  or  three  hours.  This  generally 
gives  the  purest  and  finest  colors  for  plumb  tabs.  When  the 
wood  is  ground,  the  decoctions  are  generally  made  by  pouring 
boiling  water  upon  it.  Some  dyers  put  the  quantity  required 
into  a  tub;  fill  this  with  boiling  water;  allow  the  grounds  to 
settle,  and  decant  the  solution;  but  the  best  method  is  to  use 
a  basket,  lined  with  cloth;  the  logwood  is  put  into  the  basket, 
and  boiling  water  is  poured  upon  it ;  the  clean  decoction  filters 
through.  No  more  logwood  should  be  taken  than  what  is  to 
be  used  at  the  time,  as  it  loses  its  dyeing  properties  by  stand- 


PREPARATION  OF  DECOCTIONS. 


311 


ing;  the  color  passes  from  a  rich  wine  hue  to  a  yellow-brown, 
and  assumes  a  syrupy  appearance ;  and  colors  dyed  by  it  after 
this  change  takes  place  are  always  wanting  in  brilliancy;  be- 
sides, it  takes  a  greater  quantity  of  stuff*  to  produce  the  same 
depth  of  shade.  This  may  be  caused  by  a  partial  decomposition 
of  the  coloring  matter,  or  of  the  other  ingredients  of  the  wood 
reacting  upon  the  coloring  matter. 

Parkes,  in  his  Chemical' Essays,  has  the  following  observa- 
tions bearing  upon  this  subject:  ''Considerable  advantage  is 
derived  by  the  woollen  dyers  from  the  use  of  water  in  the 
preparation  of  rasped  logwood.  As  the  wood  is  cut  into  chips, 
they  sprinkle  it  abundantly  with  water,  and  in  that  moistened 
state  it  is  thrown  into  large  heaps,  and  sometimes  into  bins  of 
great  size,  where  it  is  suffered  to  lie  as  long  as  is  convenient. 
By  this  treatment  the  chips  become  heated,  or  they  ferment,  as 
the  dyers  call  it,  and  thus  undergo  a  very  remarkable  change  ; 
for,  after  having  lain  a  few  months  in  this  state,  they  give  out 
the  coloring  matter  in  the  dyeing  copper  much  more  easily  ; 
and  any  given  quantity  of  such  chips  will  produce  a  more  in- 
tense dye  than  could  have  been  obtained  from  an  equal  quan- 
tity of  chips  which  had  not  been  thus  heated.  It  is  difficult  to 
account  for  this,  unless  we  suppose  that  the  water  becomes  in 
part  decomposed,  and  that  its  oxygen,  uniting  with  the  vege- 
table coloring  matter,  renders  it  more  intense."  We  have  found 
that,  by  damping  the  wood  with  boiling  water  a  little  before' 
pouring  the  necessary  quantity  of  boiling  water  upon  it,  the 
wood,  in  the  language  of  the  dyer,  is  much  better  bled ;  but  we 
consider  this  to  result  from  softening  the  particles  of  wood,  and 
so  making  the  coloring  matter  more  easily  dissolved  by  the 
water  afterwards  applied.  Whether  anything  more  is  effected 
by  the  practice  noticed  by  Mr.  Parkes,  or  if  any  decomposition 
takes  place,  we  cannot  say.  If  by  fermentation  is  meant  the 
formation  of  acids,  we  know  that  acids  do  not  produce  the  effects 
stated  ;  but  if  it  is  a  fermentation  caused  by  the  decomposition 
of  any  substance  having  nitrogen  as  a  constituent,  the  result 
would  be  the  formation  of  ammonia,  a  substance,  as  we  have 
already  noticed,  which  has  a  powerful  influence  upon  the  color- 
ing matter  of  logwood,  and  extracts  it  very  rapidly — a  property 
possessed,  indeed,  by  all  alkalies  and  alkaline  earths.  This  is 
well  known  to  dealers  in  logwood,  who  occasionally  sprinkle  it 
with  water  containing  a  little  lime,  which  gives  the  wood  a 
richness  in  color,  so  that  the  poorest  woods,  thus  doctored,  appear 
equal  to  those  of  the  finest  quality.  Such  wood,  however, 
never  produces  good  light  shades.  The  presence  of  an  alkali 
may  be  detected  in  logwood,  by  taking  a  little  in  a  tumbler, 
and  allowing  it  to  steep  for  a  few  hours  in  distilled  water,  and 
hen  trying  the  solution  with  delicate  test-papers. 


312 


LOGWOOD. 


This  practice  of  putting  lime-water  upon  the  ground  logwood 
may  be  one  reason  why  decoctions  of  ground  logwood  lose 
their  coloring  power  so  rapidly  by  standing  ;  as  all  alkaline 
matters  in  connection  with  logwood,  although  they  give,  in 
the  first  place,  a  richness  of  color,  soon  pass  into  a  brown,  and 
the  color  decays. 

There  is  yet  no  simple  and  accurate  process  for  testing  log- 
wood which  could  be  introduced  into  the  dye-house,  although 
there  are  few  substances  of  apparently  greater  variety.  The 
differences,  however,  often  consist  only  in  the  moisture  and  in 
the  doctoring. 

The  method  generally  adopted  for  judging  of  the  value  of 
logwood  consists  in  comparing  the  color  of  samples  of  yarn 
dyed  by  different  specimens  of  it.  A  given  weight  of  each  of 
the  logwood  samples  is  macerated  in  boiling  water  and  then  an 
equal  quantity  of  mordanted  cotton  is  dyed  by  each  of  the 
several  decoctions;  the  depth  and  kind  of  color  produced  are 
the  test  of  the  quality.  With  care  this  method  is  very  satis- 
factory for  practical  purposes;  but  an  oversight  is  often  made 
in  these  trials  in  not  taking  the  quantity  of  water  which  is  in 
the  sample.  It  is  necessary  that  ground  logwood  should  be  a 
little  damp,  to  prevent  it  flying  away  as  dust,  but  it  is  also 
requisite  to  avoid  paying  for  the  water  put  into  it  at  the  same 
rate  as  for  logwood  ;  care  ought  therefore  to  be  taken  not  only 
to  dry  the»samples,  but  also  to  ascertain  the  water  contained  in 
them.  This  will  be  rendered  more  apparent  by  stating  the 
results  of  some  experiments  directed  to  this  point.  Samples 
of  wrood,  as  imported,  before  being  ground  or  chipped,  kept  at 
a  temperature  of  212°,  as  long  as  it  decreased  in  weight,  gave 
a  loss  ranging  from  9  to  16  per  cent.;  average  12  per  cent. 
The  moisture  in  ground  logwood,  as  supplied  to  the  dver, 
ranges  from  88  to  46  per  cent. ;  average  42  per  cent. ;  so  that 
the  amount  of  water  added  averages  30  per  cent. 

The  moisture  may  be  tried  by  putting  a  weighed  sample  of 
the  ground  wood  upon  a  piece  of  paper,  or  on  a  plate  for  some 
hours  in  the  drying-stove,  when  no  wet  goods  are  in  it.  In 
the  experiments,  of  which  the  results  are  given  above,  we  used 
a  water-bath,  which  is  preferable.  Samples  to  be  tried  ought 
all  to  be  previously  submitted  to  the  drying  process. 

Water  is  not  the  only  thing  added  to  logwood;  a  little  lime 
is  occasionally  added  to  the  water,  which  gives  the  logwood  a 
bloom,  and  makes  it  appear  better  than  it  really  is.  In  burn- 
ing samples  of  ground  logwood,  and  deducting  the  water  that 
had  been  added,  we  have  found  the  ash  to  vary  from  2  to  2.3 
per  cent. 

Were  the  usual  mode  of  testing,  by  trying  the  depth  of  color 


THE  PLUMB  TUB. 


313 


to  be  applied  with  a  doctored  sample,  and  one  not  doctored,  say 
half  an  ounce  of  each,  the  ground  wood  in  each  case  put  into 
a  small  basin,  and  filled  with  boiling  water,  and  the  decoction 
used  to  dye  a  skein  of  cotton,  the  doctored  sample  will  be  found 
to  yield  its  color  immediately  to  boiling  water,  and  the  other 
slower — in  which  case  the  former,  having  yielded  all  its  color 
at  once,  may  give  a  deeper  dye  than  the  other,  and  yet  actually 
contain  less  coloring  matter.  The  proper  way  of  proceeding 
is  to  take  100  grains  of  each  sample,  put  the  whole  quantity 
upon  a  filter,  and  pour  boiling  water  upon  it  as  long  as  the 
water  passing  through  is  colored,  then  use  all  the  liquor  with 
cotton  so  mordanted  as  to  take  up  all  the  color.  The  remain- 
ing logwood  thus  exhausted  should  be  nearly  colorless;  and  by 
drying  and  weighing  it,  an  approximation  to  the  quantity  of 
color  may  be  obtained.  Good  logwood  loses  about  12.5  per 
cent,  in  this  way  after  deducting  all  water. 

We  have  already  referred  to  the  plumb  tub  and  plumb 
spirits,  and  stated  that  if  a  salt  of  tin  be  put  into  a  hot  solu- 
tion of  logwood,  there  is  a  precipitate  formed.  If  the  neutral 
salt  of  tin  be  added  to  logwood,  cold,  there  is  a  precipitate 
formed  of  a  beautiful  wine  color;  but  this  precipitate  is  solu- 
ble in  dilute  muriatic  acid — hence  the  reason  why  so  much 
acid  is  used  for  the  tin  in  the  preparation  of  the  plumb  spirits. 

The  plumb  tub  is  prepared  as  follows:  A  decoction  of  log- 
wood is  made  by  boiling,  continuing  the  ebullition  until  the 
specific  gravity  is  8°  of  Twaddell.  This  decoction  is  allowed, 
to  stand  till  it  is  perfectly  cold;  a  quantity  of  tarry  matter  pre- 
cipitates in  the  cooling,  so  that  the  clear  liquor  requires  to  be 
decanted.  There  is  then  added  to  it  a  quantity  of  plumb 
spirits,  sufficient  to  raise  the  specific  gravity  to  about  14°  of 
Twaddell.  After  standing  twenty-four  hours,  it;  is  fit  for  use 
—  which  consists  simply  in  immersing  the  goods  for  a  short 
time,  then  taking  them  out  and  washing  them.  As  this  com- 
pound of  tin  and  logwood  is  held  in  solution  by  the  free  acid 
of  the  spirits,  whenever  the  cotton  impregnated  with  it  is  put 
into  water,  the  dye  is  rendered  insoluble;  the  repeated  wash- 
ing is  necessary  to  carry  oft*  all  free  acid.  Occasionally  in  pre- 
paring the  plumb  tub,  it  happens  from  some  cause,  as  want  of 
care  in  making  the  spirits  or  the  decoction,  that  the  logwood 
gets  all  precipitated.  This  precipitate  may  all,  or  the  greater 
part  of  it,  be  dissolved  by  adding  hydrochloric  acid;  but  then 
the  tint  of  color  produced  upon  the  goods  will  not  be  so  blue; 
it  will  be  more  red,  with  a  tendency  to  brown.  Hydrochloric 
or  nitric  acid  added  to  a  cold  solution  of  logwood,  will  make  a 
plumb  tub  without  tin;  but  there  being  no  base,  and  the  solu- 
tion being  soluble  in  water,  it  does  not  form  a  good  dye,  being 


3U 


BRAZIL-WOODS. 


nearly  all  removed  by  washing.  But  if  the  goods  be  previously 
prepared  with  a  base,  colors  of  various  tints  may  be  obtained 
by  this  means — which  may  be  resorted  to  when  a  plumb  tub  is 
not  at  hand. 

Brazil-Woods. 

The  Bois  de  Pernambouc  of  the  French,  and  the  Brazilien- 
holz  of  the  German  dyers.  There  are  several  varieties  of  this 
wood,  which  are  distinguished  from  each  other  by  the  name  of 
the  locality  where  they  are  obtained,  such  as  Pernambuco, 
Japan,  &c.  In  the  dye-house  they  are  often  all  named  peach- 
wood,  from  an  inferior  sort  often  used,  and  obtained  from 
Campeachy. 

The  Brazil-wood  tree,  called  by  botanists  Csesalpinia  crista, 
is  an  American  production,  and,  according  to  some  authorities, 
gave  the  name  to  the  country  in  which  it  grows,*  Brazil,  The 
Portuguese  government  discovered  the  value  of  the  wood,  and 
made  it  an  object  of  royal  monopoly;  hence  it  came  by  the  now 
nearly  forgotten  name  of  Queen-wood.  It  grows  mostly  in  dry 
places  and  amongst  rocks;  its  trunk  is  large,  crooked,  and  full 
of  knots. 

The  following  paragraph  upon  these  woods  is  taken  from 
Bell's  Geography:  uThe  ibiripitanga,  or  Brazil  wood,  called  in 
Pernambuco  the  pao  da  rainha  (Queen's- wood),  on  account  of 
its  being  a  government  monopoly,  is  now  rarely  to  be  seen 
within  many  leagues  of  the  coast,  owing  to  the  improvident 
manner  in  which  it  has  been  cut  down  by  the  government 
agents,  without  any  regard  being  paid  to  the  size  of  the  tree 
or  its  cultivation.  It  is  not  a  lofty  tree.  At  a  short  distance 
from  the  ground,  innumerable  branches  spring  forth  and  ex- 
tend in  every  direction  in  a  straggling,  irregular,  and  unpleas- 
ing  manner.  The  leaves  are  small  and  not  luxuriant;  the 
wood  is  very  hard  and  heavy,  takes  a  high  polish,  and  sinks  in 
water;  the  only  valuable  portion  of  it  is  the  heart,  as  the  out- 
ward coat  of  wood  has  not  any  peculiarity.  The  name  of  this 
wood  is  derived  from  brasas,  a  glowing  fire  or  coal — its  botani- 
cal name  is  Gsesalpinia  brasileta.  The  leaves  are  pinnated;  the 
flowers  white  and  papilionaceous,  growing  in  a  pyramidal 
spike;  one  species  has  flowers  variegated  with  red.  The 
branches  are  slender,  and  full  of  many  prickles.  There  are 
nine  species." 

The  species  brasileto  is  inferior  to  the  crista;  it  grows  in 
great  abundance  in  the  West  Indies.    The  demand  for  this 


Southey's  History  of  Brazil,  vol.  i. 


BREZILIN. 


315 


wood  a  few  years  ago  was  so  great,  owing  to  its  being  a  little 
cheaper  than  the  other,  that  nearly  the  whole  of  the  trees  in 
the  British  possessions  were  cut  down  and  sent  home — which 
Mr.  Bell  very  justly  terms  improvidence.  It  is  not  now  so 
much  used,  and  is  consequently  scarcer  in  the  market. 

The  wood  known  in  commerce  as  Pernarnbuco  is  most  es- 
teemed, and  has  the  greatest  quantity  of  coloring  matter.  It  is 
hard,  has  a  yellow  color  when  newly  cut,  but  turns  red  by  ex- 
posure to  the  air.  That  kind  termed  Lima-wood  is  the  same  in 
quality.  Sapan-wood  grows  in  Japan,  and  in  quality  is  next 
to  the  two  named  above.  It  is  not  plentiful,  but  is  much  valued 
in  the  dye-house  for  reds  of  a  certain  tint;  it  gives  a  very 
clear  and  superior  color.  The  quantity  of  ash  that  these  two 
qualities  of  wood  contain  is  worthy  of  remark.  Lima-wood, 
as  imported,  gives  the  average  of  2.7  per  cent.,  while  Sapan- 
wood  gives  only  1.5  per  cent.;  in  both  the  prevailing  earth  is 
lime.  The  quantity  of  moisture  in  the  wood  averages  about 
10  per  cent.  That  in  the  ground  wood  in  the  market  about  20 
per  cent. 

Peach-wood,  or  Nicaragua,  and  sometimes  termed  Santa 
Martha-wood,  is  inferior  to  the  other  two  named,  but  is  much 
used  in  the  dye-house,  and  for  many  shades  of  red  is  preferred, 
although  the  coloring  matter  is  not. so  great.  It  gives  a  bright 
dye.  The  means  of  testing  the  quality  of  these  goods  by  the 
dyer  is  similar  to  that  described  for  logwood,  with  the  same 
recommendations  and  precautions. 

The  world  is  much  indebted  to  the  French  chemists  for  their 
valuable  researches  into  the  coloring  matters  of  the  dye-woods. 
M.  Chevreul  long  since  obtained  the  coloring  matter  from  Bra- 
zil-wood by  the  following  process:  41  Digest  the  raspings  of  the 
wood  in  water  till  all  the  coloring  matter  is  dissolved,  and 
evaporate  the  infusion  to  dryness,  to  get  rid  of  a  little  acetic 
acid  which  it  contains.  Dissolve  the  residue  in  water,  and  agi- 
tate the  solution  with  litharge,  to  get  rid  of  a  little  fixed  acid 
which  it  contains.  Evaporate  again  to  dryness,  digest  the 
residue  in  alcohol,  filter  and  evaporate  to  drive  off  the  alcohol. 
Dilute  the  residual  matter  with  water,  and  add  to  the  liquid  a 
solution  of  glue,  till  all  the  tannin  which  it  contains  is  thrown 
down;  filter  again  and  evaporate  to  dryness,  and  digest  the 
residue  in  alcohol,  which  will  leave  undissolved  any  excess  of 
glue  which  may  have  been  added.  This  last  alcoholic  solution 
being  evaporated  to  dryness,  leaves  brezilin,  the  coloring  matter 
of  the  wood,  in  a  state  of  considerable  purity." 

Brezilin  is  very  soluble  both  in  water  and  alcohol,  but,  from 
the  hardness  of  the  wood,  the  coloring  matter  is  not  completely 
extracted  except  by  boiling;  even  the  method  recommended 


316 


BRAZIL-WOODS. 


for  logwood  does  not  dissolve  all  the  brezilin.  The  decoction 
when  boiled  has  a  deep-red  color,  but  passes  into  a  rich  yellow- 
red  by  standing.  Acids  give  this  solution  a  yellowish  color, 
but  render  it  unfit  for  dyeing  operations.  Alkalies  communi- 
cate a  violet  color  which  is  very  fugitive: — 

Protosulphate  of  iron    .    .    Dark  purple,  not  changed  by 

standing. 

Persulphate  of  iron    I    .    .    Blackish-brown,  permanent. 
Chloride  of  tin      ....    Changes  to  a  deep  crimson. 
Chloride  of  tin      .        .    .    With  warmed  liquor,  a  deep- 
red  precipitate. 
Acetate  of  copper  ....    Dark  purple. 

Since  these  researches  by  Chevreul,  M.  Preisser  has  investi- 
gated these  substances  with  great  minuteness,  and  gives  it  as 
his  opinion  that  the  coloring  matter  of  these,  as  well  as  of  the 
other  woods,  are  oxides  of  a  colorless  base.  Thus  brezilin  is 
the  oxide  of  a  base  which  is  without  color,  and  which  he  terms 
brezilein.    Their  compositions  are  :  — 

C.      H.  O. 

Brezilein — Colorless  base  .  .  .  =36  14  12 
Brezilin — Colored  substance     .    .  =36    14  14 

It  will  thus  appear  that  the  one  is  converted  into  the  other  by 
absorbing  two  proportions  of  oxygen,  and  that  the  reactions 
are  allied  to  those  of  indigo  and  logwood  already  described. 

The  action  of  chromic  acid,  and  of  the  chromates  upon  bre- 
zilin, is  remarkable;  they  decompose  each  other,  and  produce 
a  beautiful  reddish-brown.  The  action  of  bichromate  of  potash 
with  the  decoction  of  Brazil-wood  has  long  been  taken  advan- 
tage of  in  calico  printing,  and,  by  proper  modifications,  may 
also  be  applied  in  the  dye-house.  The  remarks  upon  the  pure 
coloring  matter  are  applicable  to  the  decoction  of  the  wood  ; 
but  the  wood  contains  other  matters  (small  portions  of  astrin- 
gent substance),  which  are  also  soluble  in  the  water,  and  which, 
accordingly,  modify  to  a  great  extent  the  results  produced  by 
the  combined  action  of  the  decoction  and  the  pure  coloring 
principle — a  circumstance  which  should  be  constantly  borne  in 
mind  by  the  dyer.  It  is  known  that  decoctions  of  Brazil-wood 
improve  by  standing,  often  to  the  extent  of  giving  a  half  more 
effect  as  a  dye;  which  issupposed  to  be  owing  to  the  oxidation 
and  deposition  of  the  tannin,  and  other  foreign  matters  injurious 
to  the  color. 

The  nitrates  of  the  metals  almost  all  destroy  the  red  color  of 
Brazil-wood,  turning  it  into  a  dirty  yellow.  The  salts  of  potash, 
soda,  and  ammonia,  change  the  decoction  into  a  rose  color, 


SANTAL-WOOD — BARWOOD. 


317 


which  soon  passes  away  by  standing.  Alum  throws  down  a 
bulky  red  precipitate.  This  substance,  and  the  chloride  of  tin, 
are  considered  the  proper  mordants  for  Brazil-wood;  but  all 
the  colors  obtained  by  this  wood  are  exceedingly  fugitive, 
losing  their  brilliancy  on  a  short  exposure  to  the  air.  The  sun 
has  a  very  powerful  influence  upon  colors  d)^ed  by  this  wood. 
By  a  short  exposure,  the  red  color  assumes  a  blackish  tint, 
passes  into  a  brown,  and  fades  away  into  a  light  dun  color. 
These  changes  are  supposed  to  be  from  the  coloring  matter 
being  decomposed  into  water  and  some  other  volatile  sub- 
stance, leaving  a  part  of  the  carbon  free,  which  produces  the 
black  ;  heat  is  also  very  destructive  to  this  color;  nevertheless, 
the  consumption  of  this  species  of  wood  is  very  great,  espe- 
cially for  dyeing  what  are  termed  fancy  reds. 

Santal  or  Sandal-Wood, 

Commonly  called  saunders-wood,  is  a  native  of  the  East 
Indies.  It  differs  from  Brazil-wood  in  many  of  its  properties  ; 
it  is  very  hard,  and  gives  but  a  weak  decoction  in  water. 
The  coloring  matter  of  this  wood  is  different  from  that  of 
Brazil-wood  ;  its  composition  is — 

Carbon.  Hydrogen.  Oxygen. 

16  8  32 

and  is  termed  santaline.  It  reacts  with  the  salts  of  alumina, 
and  gives  red  precipitates,  which  have  more  of  a  violet  tint 
than  those  of  brezilin ;  but  it  does  not  react  in  the  same  man- 
ner with  the  chromates.  Santaline  is  much  more  soluble  in 
solutions  of  the  astringent  substances  than  in  water  ;  it  is, 
therefore,  boiled  along  with  sumach,  and  is  frequently  used  for 
woollens  in  dyeing  browns  and  other  mixed  colors  containing 
red.  According  to  the  investigations  of  the  French  chemists, 
this  wood  is  a  variety  of  barwood,  at  least  the  coloring  matter 
y  is  of  trfe  same  composition. 

Barwood. 

This  wood  is  brought  principally  from  Sierra  Leone.  Its 
coloring  matter  has  been  examined  by  MM.  Girardin  and 
Preisser,  who  considered  it  the  same  as  santaline.  MacCulloch, 
in  his  (commercial  Dictionary,  makes  a  distinction  between  bar- 
wood  and  camwood  ;  but  they  are  found  to  be  the  same  in 
chemical  composition,  only  coming  from  two  different  places. 

The  following  is  MM.  Girardin  and  Freisser's  description  of 
this  wood : — 


818 


BARWOOD. 


"  This  wood,  in  the  state  of  a  coarse  powder,  is  of  a  bright- 
red  color,  without  any  savor  or  smell.  It  imparts  scarcely  any 
color  to  the  saliva. 

"Cold  water,  in  contact  with  this  powder,  only  acquires  a 
fawn  tint  after  five  days'  maceration  ;  100  parts  of  water  only 
dissolve  2.21  of  substances  consisting  of  0.85  coloring  matter 
and  of  1.36  saline  compounds.  Boiling  water  becomes  more 
strongly  colored  of  a  reddish-yellow,  but  on  cooling  it  deposits 
a  part  of  the  coloring  principle  in  the  form  of  a  red  powder. 
100  parts  of  water  at  212°  dissolve  8.86  of  substances  consist- 
ing of  7.24  coloring  principle  and  1.62  salts,  especially  sulphates 
and  chlorides.  On  macerating  the  powder  in  strong  alcohol, 
the  liquid  almost  immediately  acquires  a  very  dark  vinous-red 
color.  To  remove  the  whole  of  the  color  from  fifteen  grains  of 
this  powder,  it  was  necessary  to  treat  it  several  times  with 
boiling  alcohol.  The  alcoholic  liquid  contained  0.23  of  color- 
ing principle  and  0.004  salt;  barwood  contains,  therefore,  23 
per  cent,  of  red-coloring  matter,  whilst  saunders-wood,  accord- 
ing to  Pelletier,  only  contains  16.75.  ^ 

16  The  alcoholic  solution  behaves  in  the  following  manner 
towards  reagents : — 

Produces  a  considerable  yellow 
opalescence.  The  precipitate 
is  redissolved  by  the  fixed 
alkalies,  and  the  liquor  ac- 
quires a  dark  vinous  color. 

Fixed  alkalies  Tarn  it  dark  crimson  or  dark 

violet. 

Lime-water  Ditto. 

Sulphuric  acid  Darkens  the  color  to  a  cochineal 


Distilled  water,  added  in  great 
quantity  


Sulphureted  hydrogen 
Salt  of  tin  


red. 

Acts  like  water.  . 
Blood-red  precipitate. 


Chloride  of  tin  Brick-red  precipitate. 

Acetate  of  lead  Dark-violet  gelatinous  precipi- 
tate. 

Salts  of  the  protoxide  of  iron     Very  abundant  violet  precipi- 
tates. 

Copper  salts  Violet  brown  gelatinous  preci- 
pitates 

.    .     An  abundant  precipitate  of  a 

brick-red  color. 
.    .     Gives   a  light    and  brilliant 

crimson  red 
.    .     Bright  red  flocculent  precipi- 
tate. 


Chloride  of  mercury 
Nitrate  of  bismuth 
Sulphate  of  zinc 


DYEING  WITH  BARWOOD.  319 

Tartar-emetic  Abundant  precipitate  of  a  dark 

cherry  color. 

Neutral  salts  of  potash     .    .     Act  like  pure  water. 
Water  of  barytes    ....     Dark  violet-brown  precipitate. 
Gelatin  Brownish-yellow  ochreous  pre- 
cipitate. 
Brings  back  the  liquor  to  a 
light  yellow,  with  a  slight 

Chlorine  \      yellowish  brown  precipitate, 

resembling  hydrated  perox- 
ide of  iron. 

"Pyroxylic  spirit  acts  on  barwood  like  alcohol,  and  the 
strongly-colored  solution  behaves  similarly  towards  reagents. 
Hydrated  ether  almost  immediately  acquires  an  orange-red 
tint,  rather  paler  than  that  with  alcohol.  It  dissolves  19.47 
per  cent,  of  coloring  principle.  Ammonia,  potash,  and  soda,  in 
contact  with  powdered  barwood,  assume  an  extremely  dark 
violet  red  color.  These  solutions,  neutralized  with  hydro- 
chloric acid,  deposit  the  coloring  matter  in  the  form  of  a  dark 
recldish-brown  powder.  Acetic  acid  becomes  of  a  dark-red 
color,  as  with  saunders-wood." 

The  difficulty  of  its  slight  solubility  in  water  is  overcome  by 
a  very  ingenious  arrangement.  The  coloring  matter,  while  hot, 
combines  easily  with  the  proto-compounds  of  tin,  forming  an 
insoluble  rich  red  color;  the  goods  to  be  dyed  are  impregnated 
with  protochloride  of  tin  combined  with  sumach ;  the  proper 
proportion  of  barwood  for  the  color  wanted  is  put  into  a  boiler 
with  water  and  brought  to  boil ;  the  goods  thus  impregnated 
are  put  into  this  boiling  water  containing  the  rasped  wood,  and 
the  small  portion  of  coloring  matter  dissolved  in  the  water  is 
irrvmediately  taken  up  by  the  goods.  The  water  thus  exhausted 
dissolves  a  new  portion  of  coloring  matter,  which  is  again 
taken  up  by  the  goods,  and  so  on,  till  the  tin  upon  the  cloth 
has  become,  if  we  may  so  term  it,  saturated ;  the  color  is  then 
at  its  brightest  and  richest  phase. 

A  good  deal  of  attention  and  skill  is  necessary  to  know  the 
exact  point  to  take  the  goods  out  of  the  bath,  otherwise  the 
dyer  may  either  have  the  color  poor,  or,  by  being  in  too  long, 
give  it  a  brown  color.  It  is  not,  therefore,  every  dyer  who  can 
dye  a  good  barwood  red. 

In  dyeing  with  this  wood,  it  must  be  in  contact  with  the 
goods;  the  particles  of  the  wood  must  mix  with  the  fibre.  To 
have  the  wood  in  a  bag,  even,  does  not  answer ;  and  therefore 
great  care  is  necessary  in  putting  the  mordanted  goods  into  the 
dyeing  bath,  that  there  be  no  loose  mordant  upon  them ;  for  if 


320 


CAMWOOD. 


there  is,  the  wood  (being  in  the  bath)  will  take  up  this  mordant 
and  become  dyed,  and  so  retain  a  corresponding  portion  of  the 
coloring  matter,  and  to  that  extent  cause  loss.  Inattention  to 
this  precaution  is,  moreover,  frequently  the  cause  of  great  ir- 
regularity in  the  shades;  and  even  with  the  greatest  care,  the 
wood- grounds  come  out  of  the  bath  richly  dyed.  Barwood  is 
not  used  along  with  other  matters  for  compound  colors,  in  the 
same  way  as  the  other  red  woods  are  for  dyeing  cotton  ;  but 
it  is  occasionally  so  used  in  dyeing  woollens.  The  dyer  has 
no  means  of  testing  the  value  of  this  dyewood,  owing  to  its 
insolubility  in  water.  In  a  piece  of  wood  as  imported,  we 
found  moisture  11  per  cent,  and  only  .0.5  per  cent,  of  ash.  In 
ground  samples,  the  moisture  ranges  about  20  per  cent,  and 
the  ash  1.2.  The  coloring  matter  is  very  soluble  in  dilute 
ammonia.  By  passing  ammonia  water  through  a  weighed 
quantity  upon  a  filter,  until  all  soluble  matters  are  dissolved 
out,  then  drying  the  residue,  the  average  of  good  barwoods 
gives — 

Wood  remains  73.4 

Water  at  212°   18.2 

Coloring  matter   8.4 


100.0 

By  neutralizing  the  ammonia,  the  color  is  precipitated  as  a 
lake. 

It  is  recommended  in  some  works  upon  dyeing  as  a  general 
rule,  that  as  all  colors  that  are  dyed  in  boilers  begin  to  take  on' 
the  dye  when  the  solution  is  lukewarm,  the  goods  should  be 
put  in  at  that  heat,  and  kept  in  till  boiling.  This  may  be  best 
in  the  case  of  woollens,  and  even  with  some  colors,  such  as 
barwood  and  madder,  upon  cotton ;  but  it  is  not  good  as  a  rule 
for  cotton.  Generally,  indeed,  the  quicker  cotton  is  dyed  the 
better,  and  when  there  is  a  mixture  of  coloring  matters  used, 
long  working  causes  that  color  which  has  the  greatest  attrac- 
tion for  the  mordant  to  prevail  at  the  expense  of  the  others, 
even  although  the  attraction  when  the  goods  were  newly  put 
into  the  mixture  may  have  been  simultaneously  equal  and 
mutual. 

Camwood 

Is  another  species  of  red-wood  sometimes  used  in  the  dye- 
house,  imported  from  Sierra  Leone.  The  color  obtained  from  it 
is  more  permanent,  and  in  many  instances  much  more  beautiful 
than  from  those  termed  Brazil-woods.  The  precipitates  from 
a  decoction  of  the  wood  are  more  yellow  than  those  afforded 
by  the  Brazil-woods — which  explains  why  the  colors  dyed  by 


FUSTIC,  OR  YELLOW  WOOD. 


821 


It  have  a  certain  degree  of  richness  not  obtained  with  the  other 
woods.  It  is  not  so  easily  affected  by  alkaline  substances,  and 
appears  to  contain  more  tannin  than  the  Brazil-woods.  With 
it — 


Protosulphate  of  iron  .    .  . 

Persulphate  

Protosalts  of  tin  


Lead  salts      .    .    .    .    .  . 

Acetate  of  copper   .    .    .  . 

Nitrate  of  silver  

Perchloride  of  mercury  .  . 
Alum  


Gives  a  brownish-black  precipi- 
tate. 

A  reddish-brown. 

Give  the  solution  a  very  bright 

carmine-red  color,  but  little 

precipitate. 
A  rich  orange  precipitate  after 

standing  some  time. 
A  light  reddish-brown. 
A  reddish-yellow  precipitate. 
Light  orange,  by  standing. 
Gives  the  solution  a  beautiful 

red  color. 


This  wood  may  also  be  used  for  browns  and  other  composi- 
tion colors  where  Brazil-wood  is  commonly  used  ;  it  is  more 
soluble  in  water,  has  other  advantageous  properties,  and  may 
be  used  as  a  substitute  for  many  other  purposes  in  which  the 
best  Brazil-woods  are  employed. 


Fustic,  or  Yellow- Wood. 

This  dyestuff  has  been  long  known.  It  is  uncertain  when  it 
was  introduced  as  a  dye-drug,  but  mention  is  made  of  it  in  a 
book  published  in  1692.  The  botanical  name  of  the  tree  which 
produces  this  drug  is  Morus  tinctoria.  It  grows  spontaneously 
in  Brazil,  and  in  several  of  the  West  Indian  Islands,  where  it 
attains  to  a  great  height.  The  wood  is  of  a  sulphur  color,  with 
orange  veins,  and  contains  two  coloring  matters;  the  one  resi- 
nous, and  not  soluble  in  water;  the  other  very  soluble  in  this 
menstruum,  producing  a  deep-yellow  color,  having  a  light 
orange  cast.  This  substance  has  been  long  used  for  dyeing 
yellow,  is  still  extensively  employed  for  producing  that  color 
upon  woollens  and  silk,  and  is  the  principal  ingredient  in  dyeing 
greens  upon  these  substances;  but  it  is  seldom  used  for  cotton. 

The  coloring  matter  of  this  wood  has  been  studied  by  M. 
Chevreui,  who  has  given  it  the  name  of  morin.  If  we  take  one 
pound  of  ground  fustic  and  boil  it  for  a  short  time  in  a  gallon 
of  distilled  water,  and  then  pass  the  solution  rapidly  through  a 
filter,  to  separate  the  woody  particles;  as  the  solution  cools  it 
becomes  turbid,  and  a  quantity  of  the  coloring  matter  is  pre- 
21 


322 


YOUNG  FUSTIC. 


cipitated.  If  allowed  to  stand  for  several  days,  a  goodly  quan- 
tity of  morin  may  be  obtained  in  a  crystalline  form.  Every 
practical  dyer  who  has  used  fustic,  knows  that  if  his  decoction 
of  this  wood  stand  over,  it  loses  its  coloring  properties,  and  that 
therefore  it  should  be  used  immediately  after  boiling.  The 
yellow  decoction  of  this  wood  gives  with  the  following  re- 


agents:— 

Alkalies   An  orange  color  with  a  green 

tint. 

Protochloride  of  tin    ...  A  reddish-yellow. 

Perchloride  of  tin   ....  A  rich  yellow. 

Alum   A  canary  yellow. 

Acetate  of  lead   An  orange-yellow,  but  dirty. 

Acetate  of  copper    ....  A  brown  tint. 

Protosalts  of  iron    ....  A   greenish-olive   tint;  which 

darkens  by  standing. 

Persalts  of  iron   The  same. 

Sulphuric  acid   A  red  precipitate,  by  standing. 

Nitric  acid   A  red  precipitate. 


The  morin  precipitated  from  the  solution,  is  soluble  in  water 
with  difficulty,  but  dissolves  freely  in  a  weak  alkali,  from  which 
it  may  be  pi*ecipitated.  The  coloring  matter  is  often  found 
crystallized  in  veins  of  the  wood.  The  base  of  this  coloring 
substance  is  also  considered  to  exist  in  the  white  state ;  but  it 
passes  into  yellow  by  absorbing  oxygen. 

This  dyewood  was  partially  superseded  for  the  dyeing  of 
yellows  upon  cotton  by  quercitron  bark,  and  both  are  now 
almost  totally  displaced  by  bichromate  of  potash  and  lead. 
There  are  still,  however,  some  greens  dyed  by  fustic  upon 
cotton  yarn.  The  yarn  is  first  dyed  blue  by  the  blue  vat,  and 
then  passed  through  a  little  pyrolignite  of  alumina  ;  it  is  next 
wrought  in  a  hot  decoction  of  fustic,  which  communicates  a 
beautiful  rich  shade  of  green. 

Light  cotton  fabrics,  as  gauzes  and  muslins,  are  also  occa- 
sionally dyed  green  by  fustic.  For  this  purpose,  the  wood  is 
used  in  the  same  manner  as  the  quercitron  bark.  Fustic  is 
also  used  with  other  woods  for  compound  shades,  as  drabs, 
fawns,  olives,  &c,  and  is  much  used  with  logwood  in  dyeing 
black,  as  well  on  cotton  as  upon  silks  and  woollens. 

Young  Fustic, 

Called  also  Venetian  sumach,  was  long  used  in  France  under 
the  name  of  fustet,  for  giving  a  yellow  dye.    These  names 


BARK,  OR  QUERCITRON. 


323 


caused  a  good  deal  of  confusion,  which  is  to  some  extent  ob- 
viated by  the  prefix  young  to  this  wood,  the  yellow-wood  being 
old  fustic.  Young  fustic  is  a  shrub  (rhus  cotinus)  which  grows 
principally  in  Italy  and  the  South  of  France,  where  it  is  culti- 
vated for  the  purposes  of  dyeing.  When  cut  down,  it  is  strip- 
ped of  its  bark  and  broken  into  small  pieces,  in  which  state  it 
is  met  with  in  commerce.  This  wood  contains  a  large  quantity 
of  yellow-coloring  matter  named  fusteric.  It  is  soluble  in  water, 
and  in  that  state  gives  the  following  reactions  with  other  sub- 
stances: namely,  with — 

Tin  salts   An  orange-yellow  precipitate. 

Iron  salts   An  olive-green  color. 

Acetate  of  lead  ....  A  yellowish-white. 

Alkalies  in  solution    .    .  Change  the  color  to  red. 

This  coloring  matter  has  a  strong  attraction  for  oxygen,  a 
property  which  affects  its  use  as  a  dye.  The  colors  being 
fugitive,  it  is  seldom  used  alone  as  a  dye,  but  as  an  assistant 
to  strike  some  particular  tint.  It  is  not  used  in  cotton  dye- 
ing. 

Bark,  or  Quercitron, 

Is  the  inner  bark  of  a  tree  (the  quercus  nigra  of  botanists) 
which  grows  spontaneously  in  North  America.  Its  dyeing 
properties  were  first  made  known  to  the  public  by  Dr.  Ban- 
croft, in  1784,  and  wTere  very  soon  appreciated.  Two  years 
after  he  obtained  an  act  of  Parliament,  vesting  in  him  the  ex- 
clusive use  and  application  of  it  for  a  certain  term  of  years. 

A  decoction  of  quercitron  bark  has  a  yellow-orange  color. 
If  the  decoction  be  made  very  strong,  it  deposits  a  portion  of 
the  coloring  matter  in  cooling.  It  contains  a  great  quantity  of 
tannin,  which  is  always  dissolved  in  the  decoction,  and  which 
gives  the  solution  of  bark  a  greater  variety  of  uses.  A  de- 
coction of  the  bark  gives  the  following  reactions  with  other 
matters : — 

Alkalies  Deepen  the  color  of  the  solution. 

Lime  A  precipitate  of  a  yellowish-red 

color. 

Protochloride  of  tin    .    .  A  yellowish-red  precipitate. 

Alum  A  slight  precipitate  cold,  but 

more  when  hot. 

Acetate  of  alumina  .  .  .  A  bulky  reddish-yellow  precipi- 
tate. 

Acetate  of  lead  ....  A  reddish-yellow  precipitate. 


324 


BARK,  OR  QUERCITRON". 


Acetate  of  copper  ...  A  greenish-yellow  precipitate. 

Salts  of  iron  Dark    olive-green  precipitates, 

passing  into  brown. 

Hydrochloric  acid  and  }    -r>        t     -n  *  • «  « 

J  .A  .      .  }•    Keddish-yellow  precipitates, 

nitric  acid  .    .    .    .  )  J         r  r 

The  pure  coloring  matter  of  bark  has  been  extracted  and 
investigated  by  Chevreul  and  Bolley.  It  is  termed  quercilrine, 
is  a  crystalline  substance  of  a  sulphur-yellow  color,  and,  like 
the  other  extractive  coloring  matters,  is  considered  to  be  the 
oxide  of  a  colorless  base.  The  composition  of  quercitrine  is 
given  as  follows: — 

Carbon.  Hydrogen.  Oxygen.  Water. 

16  8  9  1 

A  decoction  of  bark  standing  until  it  becomes  stale,  loses  much 
of  its  dyeing  properties.  The  yellow  matter  is  deposited,  and 
what  remains  in  solution  is  of  a  darker  hue,  and  gives  a  dull 
color  when  used  for  dyeing. 

Bark  was  extensively  used  in  the  dye  house  for  many  years 
for  the  purpose  of  dyeing  yellow,  and  almost  completely  super- 
seded the  use  of  fustic,  both  from  its  beauty  and  also  its  cheap- 
ness; but  its  use  for  that  purpose  has  been  superseded  by  the 
bichromate  of  potash.  Its  principal  use  now  in  the  cotton  dye- 
house  is  to  form  the  ground  for  certain  browns,  and  for  dyeing 
green  upon  light  muslin  cloth ;  but  catechu  has  now  nearly 
superseded  it  for  browns.  The  quantity  of  tannin  combined 
with  it  makes  it  very  useful  for  olives;  goods  impregnated 
with  iron,  and  passed  through  a  decoction  of  bark,  take  a  beau- 
tiful olive.  When  used  for  dyeing  green,  the  mordant  em- 
ployed is  acetate  of  alumina;  but  for  yellow,  which  is  now 
only  dyed  upon  yarn  for  particular  purposes,  the  mordant  used 
is  chloride  of  tin  (spirits). 

When  bark  is  used  for  brown  upon  yarns,  it  is  done  thus: 
The  goods  are  dyed  a  deep  yellow  by  being  steeped  in  sumach, 
and  then  passed  through  the  spirits,  out  of  which  they  are 
wrought  in  a  boiling  decoction  of  bark,  raised  with  spirits  ;  that 
is,  having  a  quantity  of  spirits  put  into  the  bark  solution. 
The  goods  are  washed  from  this,  and  afterwards  passed  through 
a  mixture  of  logwood  and  Brazil-wood,  according  to  the  shade 
of  brown  required.  And  we  would  here  draw  attention  to  a 
very  interesting  fact,  observed  first  by  Mr.  Thorn,  of  Manches- 
ter, namely,  that  amongst  the  coloring  matters  and  bases  there 
is  an  elective  affinity,  which,  if  not  studied,  will  lead  to  several 
errors.  We  quote  on  this  subject  from  ParnelTs  Applied  Che- 
mistry : — 

uBut  the  combinations  of  alumina,  &c,  with  soluble  color- 


FLA  VINE. 


325 


ing  matters  seem  to  be  cases  of  true  chemical  combination, 
taking  place  in  definite  proportions,  and  under  the  influence  of 
different  degrees  of  attractive  force  for  different  coloring  prin- 
ciples. Thus,  alumina  has  a  stronger  attraction  for  the  coloring 
principle  of  madder  than  for  that  of  logwood,  and  a  stronger 
attraction  for  that  of  logwood  than  for  that  of  quercitron. 
When  a  piece  of  cloth  impregnated  with  alumina  is  immersed 
into  a  decoction  of  quercitron  bark,  it  acquires  a  fast  yellow 
color;  if  the  same  cloth  is  washed  for  some  time  and  kept  in 
a  hot  decoction  of  logwood,  the  alumina  parts  with  the  color- 
ing principle  of  quercitron  to  combine  with  that  of  logwood, 
and  the  color  of  the  cloth  becomes  changed  from  yellow  to 
purple.  If  the  same  cloth  is  next  immersed  for  a  few  hours  in 
a  hot  infusion  of  madder,  the  alumina  parts  with  the  coloring 
principle  of  logwood  to  unite  with  that  of  madder,  the  color 
of  the  cloth  changing  from  purple  to  red.  The  quantity  of 
alumina  on  the  cloth  does  not  appear  to  diminish  while  these 
substitutions  are  taking  place.  These  interesting  facts  were 
communicated  to  me  by  Mr.  John  Thorn,  of  the  Mayfield  Print 
Works." 

Now,  the  same  law  is  applicable  when  the  mordant  is  tin ; 
so  that  a  quantity  of  goods  being  dyed  yellow  as  described, 
and  then  put  into  a  hot  solution  of  logwood,  a  quantity  of  the 
yellow  is  displaced  by  the  coloring  matters  of  the  logwood  and 
Brazil-wood.  Every  dyer  knows  when  he  has  browns  of  a 
deep  shade,  how  difficult  it  is  to  bring  them  up,  should  he  fail 
to  strike  the  proper  tint  at  the  first  dip ;  if  he  is  necessitated 
to  continue  working  in  the  logwood  and  Brazil-wood,  he  is 
very  apt  to  run  his  color  poor  in  yellow  by  dissolving  it  off; 
and  to  remedy  this  evil  he  next  adds  fustic  or  bark,  with  very 
questionable  success.  We  have  often  experienced  these  diffi- 
culties when  dyeing  browns  by  the  process  described  above, 
with  an  aluminous  mordant  upon  the  cloth  instead  of  tin. 

Flavine. 

Within  these  few  years  a  vegetable  extract  bearing  this  name 
has  been  introduced  into  the  art.  It  is  brought  from  America 
in  the  state  of  an  impalpably  fine  powder,  very  light,  and  of  a 
dun  color.  It  is  used  in  the  dye-house  as  a  substitute  for  quer- 
citron bark,  to  which,  for  some  purposes,  it  is  superior.  The 
mode  of  preparing  it  is  by  dissolving  it  in  hot  water,  with 
which  it  gives  a  sort  of  turbid  solution.  It  should  be  used 
when  newly  dissolved ;  for  if  allowed  to  stand,  it  deposits  a 
brownish-yellow  mass,  in  consequence  of  its  not  being  all  com- 


326 


WELD,  OR  WOLD. 


pletely  soluble  in  water.  If  boiled  in  distilled  water  until  all 
the  soluble  matter  is  taken  up,  and  the  clear  solution  decanted, 
it  soon  yields  a  deposit.  The  color  produced  by  flavine  is 
never  good  until  raised.  A  color  dyed  by  it  weakens  gradually 
when  a  little  sulphuric  acid  has  been  added;  but  what  remains 
retains  its  brilliancy  by  raising,  and  in  respect  of  this  property 
it  differs  from  bark. 

The  quantity  of  coloring  matter  in  flavine  is  very  great ;  its 
value  as  compared  with  bark  is  as  16  to  1,  or  one  ounce  of 
flavine  is  equal  to  one  pound  of  bark.  A  portion  burned  left 
4.4  per  cent,  of  ash;  and  a  solution  of  it  gives  the  following 
reaction  with  salts: — 

Persalts  of  iron    .    .    .  Olive-black  precipitates. 

Protosalts  of  iron  .    .    .  Deep  greenish-black  precipitates. 

Protosalts  of  tin  .    .    .  Lemon-yellow  precipitates. 

Persalts  of  tin  .    .    .    .  Orange-yellow  precipitates. 

Alumina   A  rich  yellow  precipitate. 

Acids  lighten  the  color  of  the  solution,  and  alkalies  deepen 
it,  rendering  it  redder. 

Extracts  of  Woods. 

In  order  to  save  the  cost  of  transportation,  and  at  the  same 
time  give  more  regular  and  more  easily  applied  products,  the 
coloring  matter  of  dye-woods  has  for  many  years  been  sold  in 
the  form  of  liquid  and  solid  extracts.  The  latter  are  obtained 
by  drying  in  vacuo  the  colored  solutions. 

The  decoctions  of  Brazil  wood,  according  to  Dingier,  are 
considerably  improved  by  removing  a  fawn  substance,  by 
means  of  a  small  quantity  of  milk  without  cream  added  to  the 
boiling  liquors.  The  caseine  of  the  milk  coagulates  and  falls 
to  the  bottom  of  the  pan  with  the  impurity. 

It  is  also  said,  that  ground  logwood  or  Brazil  wood,  damp- 
ened with  a  water  holding  in  solution  some  gelatine  (2  per  cent, 
of  the  weight  of  the  wood), -and  allowed  to  rest  for  several 
days,  will  give  colored  solutions,  much  better  in  quality  and  in 
amount  of  dyeing  power,  than  woods  treated  with  water  alone. 

Weld,  or  Wold. 

This  vegetable  is  extensively  cultivated  in  France,  and  many 
other  parts  of  Europe,  for  the  purpose  of  dyeing  yellow.  It  is 
found  in  commerce  in  small  dried  bundles.  The  more  slender 
the  stem  is,  the  better  is  it  considered  for  dyeing.    Both  the 


WELD,  OR  WOLD. 


327 


seeds  and  the  stems  are  used,  as  they  both  contain  the  coloring 
matter;  bat  the  seeds  are  considered  to  contain  it  in  greater 
quantity.  The  coloring  matter  approaches  very  nearly  to  that 
of  quercitron  in  chemical  properties;  and  of  all  the  vegetable 
dyes  it  is  least  acted  upon  by  acids  and  alkalies,  which  gives 
to  the  dye,  so  far  as  these  substances  are  concerned,  great  per- 
manence. But  it  has  this  counteracting  disadvantage,  that 
the  color  rapidly  fades  or  passes  away  when  exposed  to  the 
action  of  air  and  light;  it  then  becomes  oxidized,  and  in  con- 
sequence has  been  abandoned  for  almost  all  purposes  where 
bark  can  be  used.  It  is  still,  however,  occasionally  used  as  a 
yellow  dye  for  silks  and  woollens,  and  also  for  some  mixed 
colors.  A  decoction  from  weld  is  made  in  the  same  way  as 
that  of  most  other  vegetable  dyes;  the  wood,  whether  in  bunches 
or  chipped,  is  merely  put  into  a  boiler  with  water  and  boiled. 
Sometimes  the  bunches  are  put  into  a  bag  of  coarse  cloth. 
This  decoction  is  of  a  yellow  color,  with  a  reddish  tint,  and  has 
a  bitter  taste  and  a  peculiar  odor: — 

Alkalies    ....  Change  it  to  a  brighter  yellow. 

Acids   Darken  the  yellow. 

Alum   A  yellow  precipitate. 

Protochloride  of  tin  A  yellow  precipitate. 

Acetate  of  lead  .    .  A  yellow  precipitate. 

Sulphate  of  iron     .  A  yellowish-olive  precipitate. 

The  coloring  matter  of  this  dye  has  been  obtained  in  needle- 
shaped  crystals  by  sublimation,  and  is  then  termed  luteoleine. 
We  have  referred  to  a  use  to  which  weld  is  applied  in  the 
making  up  of  pastel  and  woad  vats  (page  297).  The  weld  was 
long  used  as  a  dye  for  woollens  and  silk  before  it  was  used  for 
cotton;  its  introduction  as  a  dye  for  this  substance  is  connected 
with  a  clever  fraud.  "In  the  year  1773,  the  sum  of  £2000 
was  granted  by  act  of  Parliament  to  a  Dr.  Williams,  as  a  re- 
ward for  his  discovery  of  a  fast  green  and  yellow  dye  upon 
cotton-yarn  and  thread.  This  supposed  fast  dye  was  given  by 
the  combination  of  weld  with  a  certain  mordant,  the  composi- 
tion of  which  the  patentee  was  permitted  to  conceal,  that  foreign- 
ers might  not  enjoy  the  benefit  of  his  discovery;  while  he  on 
his  part  engaged  to  supply  the  cotton  and  thread  dyers  with 
his  dye  at  a  certain  fixed  price.  The  mordant  used  was  sup- 
posed by  chemists  to  be  a  solution  of  tin  alone,  or  of  tin  and 
bismuth,  which  gives  to  weld-yellow  the  power  of  resisting  the 
action  of  acids  and  of  boiling  soapsuds,  although  it  is  not  proof 
against  the  continued  action  of  the  sun  and  air.  This  defect, 
however,  was  not  easily  discernible,  in  consequence  of  the  in- 
genious method  which,  according  to  Dr.  Bancroft,  the  -inventor 


328 


TURMERIC — PERSIAN  BERRIES. 


employed  to  obtain  a  favorable  testimony  of  the  dyers  upon 
the  subject.  He  caused  his  specimens  of  dyed  yarn  to  be 
woven  into  pocket-handkerchiefs,  and  gave  them  to  be  worn  in 
the  pockets  of  those  who  were  afterwards  to  attest  to  the  good- 
ness of  his  dye;  and,  as  handkerchiefs  worn  in  pockets  were 
not  exposed  to  the  action  of  the  sun  and  air,  this  want  of  per- 
manence was  not  discovered  until  some  time  after  the  reward 
had  been  paid  for  an  invention  which  proved  of  little  or  no 
value." 

Turmeric. 

This  is  another  substance  formerly  used  in  dyeing.  It  is 
principally  brought  from  the  East  Indies  and  from  China.  It 
is  the  roots  of  a  plant  named  curcuma  langa,  and  resembling 
ginger;  it  is  reduced  to  powder,  and  in  this  state  is  met  with 
in  the  market.  The  coloring  matter  is  extracted  by  boiling  in 
water;  and  decoctions  of  it  have  a  peculiar  smell  and  bitter 
taste.  The  color  is  very  fugitive,  fading  rapidly  in  the  air; 
and  there  is  no  proper  mordant  for  it.  We  have  occasionally 
seen  it  used  for  giving  a  peculiar  tint  to  greens  and  light  browns; 
but  this  only  could  serve  for  a  short  time.  The  coloring  prin- 
ciple of  this  vegetable  has  also  been  extracted,  and  is  known 
in  chemistry  under  the  name  of  curcumme.  A  decoction  of 
turmeric,  or  paper  dyed  with  it  and  kept  from  exposure,  is 
much  used  in  testing  for  the  presence  of  alkalies^  which  give 
to  the  dye  a  red-brown  color. 

Persian  Berries. 

These  berries  are  the  root  »of  the  rharnnus  tinctoria,  a  plant 
growing  in  the  Levant  and  South  of  France,  &c.  They  yield 
a  bright-yellow  color,  used  by  artists  and  occasionally  by  dyers  ; 
but  the  dye  is  very  fugitive.  There  are  two  kinds  of  Persian 
berries;  one  large,  plump,  and  clear  in  color,  the  other  small, 
wrinkled,  and  brown.  The  coloring  matter  of  each  kind  has 
also  certain  distinctive  properties,  caused,  it  is  believed,  by  the 
one  being  in  full  maturity,  the  other  unripe.  The  large  and 
mature  berries  are  the  best,  giving  a  greater  quantity  of  dye, 
and  a  superior  quality  of  color.  The  coloring  matters  ex- 
tracted from  the  two  varieties  are  named  ckryso-rhamnine  and 
xantho-rhamnine.  These  have  some  interesting  reactions  with 
bichromate  of  potash,  and  other  oxidizing  agents. 


SAFFLOWER,  OR  CARTHAMUS. 


S29 


Safflower,  or  Carthamus. 

This  is  an  annual  plant,  cultivated  in  Spain,  Egypt,  and  the 
Levant.  There  are  two  varieties  of  it,  one  having  large  leaves, 
and  the  other  smaller  ones  ;  the  latter  is  the  best.  It  is  only  the 
flower  of  this  plant  that  is  used  for  dyeing.  When  the  flowers 
are  gathered,  they  are  squeezed  between  two  stones  to  express 
their  juice;  they  are  afterwards  washed  with  spring  water; 
next  taken  in  small  quantities  and  pressed  between  the  hands 
and  laid  out  upon  mats  to  dry.  These  cakes  are  covered  up 
during  the  day  to  prevent  the  sun  from  shining  upon  them — 
which  would  not  only  destroy  the  color,  but  dry  the  cakes  too 
much,  and  thereby  cause  further  deterioration.  They  are  kept 
exposed  to  the  dews  of  night,  and  turned  over  occasionally, 
till  dried  to  the  proper  point,  when  they  are  packed  up  for  the 
market.    It  is  in  this  state  they  are  procured  by  the  dyer. 

Safflower  contains  two  coloring  substances.  The  one  is  yel- 
low, very  soluble  in  water,  and  of  no  use  to  the  dyer.  To  free 
the  safflower  from  this  yellow-coloring  substance  is  a  particular 
part  in  the  manipulation  of  this  dyestuff.  The  other  coloring 
substance  is  red,  and  is  extracted  from  the  vegetable  after  the 
yellow  substance  has  been  washed  away,  by  means  of  alkaline 
carbonates.  This  substance  is  used  very  extensively  for  dye- 
ing the  various  shades  of  pinks,  crimsons,  roses,  &c,  upon  silk, 
and  also  for  the  same  colors  upon  cotton,  with  lavender,  lilac, 
and  pearl-white.  The  mode  of  preparing  safflower  for  the  pur- 
pose of  extracting  the  red  matter  from  it,  was  for  a  long  time 
that  recommended  by  Berthollet,  and  followed  by  all  other 
writers  upon  the  subject;  namely,  putting  a  quantity  into  a 
fine  bag,  "tramping"  it  with  the  feet  in  water  until  the  yellow 
color  was  dissolved  and  washed  away;  the  mass  left  was  then 
treated  with  an  alkali  to  extract  the  red  matter.  But  although 
this  red-coloring  matter  is  insoluble  in  water,  it  will  be  found 
that  the  bag  in  which  it  is  tramped  becomes  a  deep  crimson- 
red,  which  can  only  be  produced  by  its  imbibing  this  red  mat- 
ter. It  proceeds,  we  think,  from  a  very  fine  powder,  probably 
carthamine,  adhering  to  the  stuff  like  the  pollen  of  the  flower, 
and  which  floats  away  in  the  water.  It  is  much  heavier  than 
the  ordinary  carthamine,  and  collects  as  a  sediment  at  the  bot- 
tom of  the  vessels  used  to  hold  the  safflower;  but  when  tramped 
in  bags,  this  powder  is  expressed  and  imbibed  by  the  bag, 
which  becomes  strongly  dyed,  thereby  causing  a  loss  of  the 
dye.  To  avoid  this,  the  safflower  is  now  put  into  a  tub  with- 
out any  bag,  with  as  much  water  as  will  cause  the  whole  to 
float  freely.    A  very  little  tramping  or  agitation  is  sufficient  to 


330 


SAFFLOWER,  OR  CARTHAMUS. 


reduce  the  cakes  to  a  soft  flocculent  mass,  which  is  the  sole  use 
of  tramping.  It  is  next  removed  to  a  cask  or  tub,  provided 
with  a  false  bottom,  covered  with  fine  haircloth.  In  the  lower 
or  true  bottom,  is  a  plug-tap.  This  vessel  is  filled  with  clean 
water,  which  is  let  out  by  the  ping  at  the  bottom;  it  is  filled 
again,  and  so  on,  until  the  water  passing  through  is  not  colored 
yellow.  After  this,  there  is  put  into  it  a  measured  quantity  of 
pure  water — about  three  gallons  to  the  pound  of  safflower — in 
which  is  dissolved  a  little  carbonate  of  soda,  or  carbonate  of 
potash  (pearlash  does  well),  about  an  ounce  to  the  pound  of 
safflower.  Some  kinds  require  less  than  others  ;  but  care  ought 
to  be  taken  that  too  much  is  not  used,  as  it  destroys  the  bright- 
ness of  the  color.  This,  being  dissolved  in  water,  is  put  into 
the  tub  containing  the  safflower,  well  stirred,  and  allowed  to 
stand  for  about  seven  hours;  the  ping  is  then  taken  out,  and 
the  clear  liquor  drawn  into  a  proper  vessel.  This  liquor  con- 
tains the  red  dye  which  has  been  extracted  by  the  alkali.  The 
remaining  safflower  is  afterwards  washed  by  pouring  upon  it  a 
little  more  water  made  slightly  alkaline,  and  allowed  to  steep 
a  short  time;  but  if  fine  light  colors  are  to  be  dyed  directly 
from  the  solution,  this  second  extract  does  not  answer  so  well, 
as  the  shade  is  not  so  pure.  This  second  extract  is  commonly 
kept  and  used  instead  of  clear  water  for  the  next  parcel  of 
safflower;  or,  if  it  is  not  wanted  for  this  purpose,  a  little  acid  is 
added  to  the  liquor,  and  a  piece  of  old  cotton  is  allowed  to 
steep  in  it  until  it  has  extracted  all  the  coloring  matter,  which 
is  afterwards  recovered  for  use,  as  will  presently  be  described. 

The  liquor  extracted  from  the  safflower  contains  both  red 
and  yellow-coloring  matter.  For  this  reason  silk  goods  are 
not  dyed  directly  by  this  extract,  as  the  silk  takes  up  a  por- 
tion of  the  yellow,  which  renders  the  color  more  of  a  brick  hue 
than  is  due  to  the  rose  and  pink.  To  dye  silks,  any  old  cot- 
ton yarn  is  dyed  first  by  the  safflower  extract;  the  cotton  takes 
up  nothing  except  the  red.  This  cotton  is  then  thoroughly 
washed  in  cold  water  till  the  water  coming  from  it  is  perfectly 
clear;  it  is  then  steeped  for  a  little  in  water  made  slightly  alka- 
line by  carbonate  of  soda  or  potash,  which  extracts  the  red 
from  the  cotton,  and  forms  the  dyeing  solution  for  silk.  The 
silk  to  be  dyed  pink,  generally  receives  a  bottom,  or  ground,  by 
passing  it  through  a  weak  solution  of  cudbear  or  archil,  so  as 
to  form  a  flesh  or  light  lavender  color — the  depth  being  regu- 
lated according  to  the  shade  of  pink  wanted.  It  is  then  put 
through  the  safflower  solution,  which  must  previously  be  ren- 
dered acid  by  a  little  lemon-juice,  vinegar,  or  sulphuric  acid. 
When  the  safflower  liquor  is  exhausted,  the  silk  is  washed  in 
cold  water,  and  finished  by  passing  through  a  little  water  made 


SAFFLOWER,  OR  CARTHAMUS. 


331 


acid  by  lemon-juice  or  tartar;  neither  vinegar  nor  sulphuric 
acid  should  be  used  in  the  finishing  process. 

To  dye  cotton  pink,  the  liquor  is  used  as  extracted  from  the 
vegetable;  the  goods  require  no  previous  preparation,  except 
to  be  well  bleached.  The  quantity  of  liquor  used  varies  accord- 
ing to  the  shade  required;  one  pound  of  safflower  to  the  pound 
of  cotton  gives  a  dark  rose;  and  the  other  shades  in  propor- 
tion, according  to  the  tint  required. 

The  goods  are  first  wrought  in  the  alkaline  solution  for  five 
or  six  minutes,  and  then  taken  out,  and  vitriol  added  to  the 
solution  until  it  tastes  decidedly  sour;  the  goods  are  again  im- 
mersed, and  kept  working  in  this  till  the  solution  is  perfectly 
exhausted.  The  ascertaining  of  this  point  requires  a  little  ex- 
perience, as  exhaustion  is  known  by  the  operator  holding  a 
little  between  him  and  the  light;  when,  if  there  is  no  tinge  of 
red,  the  solution  is  spent.  The  goods  are  now  to  be  well  washed 
by  passing  them  through  three  or  four  tubsful  of  clear  cold 
water;  they  are  then  finished  by  passing  them  through  a  little 
water,  with  just  sufficient  tartar  to  make  the  liquid  taste  sour. 

It  must  be  borne  in  mind  that,  in  dyeing  with  saffiower;  the 
water  ought  to  be  pure  and  always  cold  ;  a  very  little  heat 
destroys  the  beauty  of  the  color;  the  goods  ought  also  to  be 
dried  cold,  and  preserved  carefully  from  sunshine.  The  colors 
obtained  by  safflower  are  the  prettiest  that  can  be  had  upon 
cotton,  but  they  are  fugitive. 

The  most  beautiful  lilacs,  puces,  and  lavenders,  are  obtained 
by  safflower  and  Prussian  blue;  but  it  is  one  of  the  most  diffi- 
cult colors  to  produce  of  equal  shade.  The  goods  are  generally 
first  dyed  a  blue  by  nitrate  of  iron  and  prussiate  of  potash  (see 
page  159),  and  then  put  through  the  safflower  solution,  previously 
made  acid ;  but  the  rapidity  with  which  the  cloth  takes  up  the 
red,  renders  it  almost  impossible  to  get  a  perfectly  even  dye. 
Another  method  is  to  dye  the  cloth  in  the  first  instance  pink, 
and  then  to  dye  it  blue.  This  method  gives  a  more  equal  dye, 
but  it  is  liable  to  serious  objections.  The  nitrate  of  iron  used 
acts  upon  the  coloring  matter,  oxidizing  and  destroying  its 
beauty  and  depth,  thus  causing  loss,  and  making  this  color  ex- 
ceedingly expensive.  Persulphate  of  iron  may  be  used  instead 
of  the  nitrate,  as  it  is  not  so  corrosive,  and  will  preserve  the 
tint  of  the  safflower  much  better. 

We  mentioned  in  our  introductory  remarks  that  one  essen- 
tial condition  in  all  dye-drugs,  before  they  could  be  used  as 
such,  was  that  they  should  be  in  solution ;  but  carthamus  is  an 
exception  to  this  rule;  when  it  is  in  a  soluble  state,  it  is  not  a 
dye,  and  must  be  rendered  insoluble  before  it  will  act  as  such. 
Although  the  cotton  is  generally  passed  through  the  alkaline 


332 


SAFFLOWER,  OR  CARTHAMUS. 


solution  before  acid  is  added,  still  this  will  not  produce  the  dye, 
but  merely  secures  an  equalized  color  under  the  rapid  action 
with  which  the  fibres  imbibe  the  solid  coloring  matter  after 
acid  is  applied. 

This  fact  favors  the  opinion  that  the  cotton  imbibes  the 
coloring  matters  in  the  same  way  as  they  are  imbibed  by  char- 
coal— the  fibres  of  the  cotton,  like  those  of  silk  and  wool,  being 
hollow. 

This  action  is  not  merely  a  capillary  attraction,  such  as 
shown  with  glass  tubes.  When  very  small  glass  tubes  are 
placed  with  their  ends  dipping  into  a  solution,  the  fluid  is 
observed  to  rise  in  them  to  a  great  height  inversely  as  the  hol- 
low diameters  of  the  tubes,  and  then  remain  stationary;  but 
if  such  tubes  are  placed  in  a  vessel  containing  the  carthamus 
in  suspension,  although  they  become  filled  with  the  liquor, 
they  do  not  exhaust  the  liquor  of  the  suspended  coloring  mat- 
ter; whereas  the  fibres  of  the  cotton,  put 
into  this  fluid,  extract  all  the  coloring  mat- 
ter from  the  water,  and  become  literally 
filled  with  it.  Thus,  if  we  take  a  vessel 
filled  with  water,  having  in  it  carthamus 
rendered  insoluble  by  an  acid,  and  suspend 
a  skein  of  cotton  in  it  for  a  few  hours,  the 
cotton  will  absorb  the  whole  coloring  mat- 
ter, and  leave  the  solution  clear — indicating 
thereby  a  distinct  power  of  attraction  ex- 
ercised between  the  fibre  and  coloring  par- 
ticles, and  also  a  circulation  of  the  fluid 
through  the  fibre  or  tubes  of  the  cotton,  which  indeed  is  true, 
more  or  less,  of  any  solid  substance  so  finely  divided  as  the 
carthamus,  and  diffused  in  water  along  with  fibres  of  cotton. 
In  the  case  of  precipitates,  the  more  dense  they  are  the  smaller 
is  the  quantity  of  solid  matter  imbibed  by  the  fibre. 

When  a  little  safflower  solution  has  an  acid  put  into  it,  and 
is  allowed  to  stand  for  a  time,  the  red  carthamine  precipitates 
as  a  fine  red  lake,  and  is  sold  as  such,  adhering  to  saucers,  for 
dyeing  ribbons,  &c.  An  extract  of  safflower  has  also  been 
recently  introduced  into  the  market  for  the  use  of  dyers,  but 
we  have,  as  yet,  had  too  little  experience  of  its  use  to  speak  of 
it  with  confidence. 

Although  safflower  colors  may  be  the  most  simple  and  easily 
dyed  of  all  kinds,  still,  from  their  delicate  reactions  with  other 
matters,  there  are  few  substances  subject  to  so  much  risk  of 
being  destroyed.  If  the  water  is  not  pure  they  will  dry  brown. 
A  little  acetic  acid,  cream  of  tartar,  or  tartaric  acid,  is  generally 
added  to  the  last  water  from  which  they  are  finished  to  preserve 


Fig.  14. 


MADDER. 


333 


the  tint;  but  too  much  or  too  little  of  these  will  produce  per- 
ceptible effects  upon  the  shades.  Great  care  has  to  be  taken 
in  the  drying;  it  should  be  done  in  a  perfectly  dry  stove,  not 
hot,  and  having  ample  space  between  each  parcel,  as  a  very 
little  steam  produces  a  yellow  surface.  The  goods  are  generally 
dried  in  the  cold;  but  care  is  necessary  that  no  sun  rays  touch 
them  ;  also  that  they  are  not  injured  by  steam  or  smoke  enter- 
ing the  sheds  where  they  are  drying.  If  all  necessary  pre- 
cautions are  not  taken,  the  dyer  has  the  mortification,  as  well 
as  expense,  of  putting  the  goods  through  at  least  the  last  acid 
solution,  and  if  they  are  much  touched,  he  is  obliged  to  redye 
them. 

The  view  that  carthamine,  or  the  red-coloring  matter  of  saf- 
flower,  is  the  oxide  of  a  colorless  base,  as  in  the  case  of  the  woods 
we  have  referred  to,  has  been  objected  to  by  many  investiga- 
tors, whose  experiments  and  reasoning  bear  evidence  of  care 
and  judgment;  thus  adding  an  interest  to  the  subject  of  vege- 
table coloring  matters,  and  showing  the  practical  man  that 
there  is  yet  before  him  much  to  be  discovered,  and  that  a  care- 
ful observation  of  all  the  reactions  and  circumstances  connected 
with  his  operations  will  stand  a  fair  chance  of  being  rewarded 
with  success. 

Madder. 

This  vegetable  rivals  indigo  as  a  dye-drug,  both  from  the 
beauty  and  permanence  of  the  colors  it  produces,  and  also 
from  the  variety  of  shades  which  it  is  capable  of  furnishing  by 
the  combinations  of  its  coloring  matters.  It  is  the  root  of  a 
plant  or  shrub  called  rubia  tinctorum,  cultivated  in  the  Levant, 
and  in  several  western  countries  of  Europe,  especially  in  France 
and  Holland.  The  East  Indies  also  furnish  a  quantity  of  it, 
and  within  a  few  years  past  a  large  importation  has  taken  place 
of  a  species  termed  rubia  memsgista,  which  contains  much  more 
coloring  matter  than  the  best  madders  of  Europe.  Its  culture 
has  often  been  attempted  in  England,  but  without  success.  In 
the  Levant  the  madder  is  collected  only  once  in  five  years ;  but 
in  France  it  is  gathered  every  three  years.  It  is  only  the  root 
of  the  plant  that  is  used  for  dyeing.  In  removing  the  root 
from  the  ground,  it  is  carefully  cleaned,  and,  when  the  season 
is  favorable,  it  is  spread  out  in  the  air  to  dry.  French  madder 
is  generally  more  imperfectly  dried  than  that  from  the  Levant, 
and  consequently  contains  more  water  of  vegetation,  and  to 
,  that  extent  it  is  comparatively  less  valuable.  It  is  sometimes 
dried  in  a  stove,  to  allow  it  to  pulverize.    The  dryness  of  the 


334 


MADDER. 


article  is  judged  of  by  the  fracture  when  a  piece  of  the  root  is 
broken  transversely  by  bending  it. 

When  the  roots  are  perfectly  dry,  if  they  are  broken  or  cut 
with  a  knife,  they  present  to  the  eye  a  reddish-yellow  color, 
which  passes  to  a  dense  brownish-red  when  the  piece  is  mois- 
tened;  but  the  more  yellow  the  root  appears  when  dry,  the 
more  coloring  matter  does  it  yield.  Madder,  when  fresh,  and 
after  being  cut  or  ground  to  powder  (in  which  state  it  is  gene- 
rally used  by  the  dyer),  has  a  heavy  sweet  smell,  with  a  some- 
what earthy  flavor.  The  product  of  grinding  is  generally  of 
three  kinds.  The  first  is  formed  of  the  epidermis,  or  skin  of 
the  roots,  and  comes  off  in  fine  filaments  by  slight  pressure. 
This  is  collected  separately,  and  forms  what  is  termed  the  mull 
—  which  is  of  very  inferior  quality.  The  second  consists  of  the 
annular  portion  of  the  root;  and  the  third  of  the  ligneous  or 
centre  portion  ;  but  generally  these  two  qualities  are  mixed. 

The  varieties  of  madder  in  commerce  are  distinguished  by 
the  name  of  the  country  from  whence  they  are  brought,  and 
by  the  appearance  they  receive  in  the  preparatory  process 
through  which  they  pass  previous  to  their  reception  at  the  dye- 
house. 

Levant  Madder  is  in  the  form  of  shoots  or  fibres,  of  greater 
or  less  length,  and  very  slender;  brown  externally,  and  pale 
orange-red  internally.  It  is  merely  cleaned  of  earth  and  dried, 
and  is  imported  from  Smyrna,  Cyprus,  &c. 

Dutch  Madder  is  ground,  but  so  very  coarsely  as  to  enable 
the  buyer  to  judge  of  the  nature  of  the  root  from  which  it  is 
prepared.  It  has  a  greasy  feel,  and  a  strong  nauseous  odor. 
Its  color  varies  from  a  brown  to  an  orange-red  ;  the  brown  is 
inferior.  It  becomes  damp  when  exposed  to  the  air,  a  property 
which  can  be  taken  advantage  of  to  judge  of  its  quality;  if  a 
little  of  it  is  exposed  in  a  damp  place,  when  good,  its  color 
passes  from  the  brownish-orange  tint  to  a  deep  red. 

The  madder  of  Holland  is  said  to  be  cropped  or  uncropped, 
according  as  the  barky  matter  of  the  root  is  separated  or  not, 
from  the  ligneous  part  in  the  process  of  pounding  through 
which  it  passes.  This  madder  is  never  employed  fresh,  but  is 
kept  at  least  a  year,  and  it  is  better  to  be  kept  three  years 
before  it  is  used.  It  may  be  kept  several  years  longer  without 
being  impaired.  During  the  first  years  it  is  kept,  it  undergoes 
some  internal  change,  and  becomes  much  brighter  in  color; 
the  powder  adheres  together,  forming  a  mass  very  difficult  to 
remove  from  the  cask,  and  swells  so  that  the  bottom  of  the 
cask  often  assumes  a  convex  form.  If  kept  for  too  long  a  time 
it  becomes  deteriorated ;  the  portion  in  contact  with  the  cask 
loses  its  brilliancy,  and  becomes  brown,  and  this  change  grad- 


MADDER. 


335 


ually  extends  through  the  whole  mass.    After  this  change  has 
taken  place,  it  is  unfit  for  dyeing  fine  reds  or  light  tints,  and 
can  be  used  only  for  dark  colors. 
The  marks  of  Dutch  madder  are — 


Alsace  Madder. — This  madder  is  met  with  in  commerce  in 
a  state  very  similar  to  that  of  Dutch  madder ;  but  although 
the  operation  of  cropping  is  generally  performed  upon  it,  that 
term  is  not  used  in  designating  it.  It  readily  absorbs  mois- 
ture from  the  air,  and  also  acquires  a  deep-red  tint  when  ex- 
posed in  a  damp  atmosphere,  as  that  of  a  cellar.  Like  Dutch 
madder,  it  is  not  employed  fresh ;  it  is  in  its  best  condition 
when  about  two  years  kept,  but  it  deteriorates  much  sooner  by 
keeping,  and  also  agglomerates  into  a  mass,  and  swells.  It  is 
inferior  to  the  madder  of  Holland ;  its  odor  is  more  penetrating, 
and  its  taste  less  sweet,  but  with  an  equal  degree  of  bitter ;  its 
color  is  more  yellow,  passing  into  brown,  with  much  less  of 
the  orange  tint.  A  little  experience  in  comparing  the  two 
sorts  soon  enables  the  dyer  to  distinguish  the  one  sort  from  the 
other. 

Madder  of  Avignon. — This  madder  is  deservedly  much 
esteemed.  There  are  several  varieties  of  it,  some  due  merely 
to  the  modes  of  preparation,  and  others  to  the  soil  on  which 
the  plant  grows.  It  is  ground  into  a  fine  powder,  which  feels 
dry  to  the  touch,  and  does  not  absorb  moisture  so  readily  as 
the  other  kinds  of  madder;  but  when  exposed  to  a  humid  at- 
mosphere, it  also  undergoes  a  change.  Its  odor  is  very  agree- 
able; the  taste  a  mixed  sweet  and  bitter,  the  last  predominat- 
ing; and  its  color  varies  from  a  pink  or  rose  hue  to  a  deep 
red,  or  reddish-brown.  The  best  qualities  are  obtained  from 
those  roots  which  grow  in  marshy  or  swampy  ground,  and 
places  enriched  by  admixture  of  animal  or  vegetable  matters. 
The  roots  from  such  a  soil  are  generally  of  a  deep  red  color, 
while  those  from  less  favorable  grounds  are  of  a  rose  or  pink 
tint.  It  is  by  mixing  these  kinds  in  different  proportions  that 
the  variety  of  madders  from  this  locality  are  obtained.  The 
several  qualities  have  various  marks,  besides  the  ordinary 
marks,  as — 

P.  to  signify  .  .  .  Palus  (marshy). 

R.       —  ...  Roseate, 

P.P.       —  ...  Pure  palus  (marshy). 

R.  P.  P.       —  ...  Purest  red  pa lus  (marshy). 


336 


MADDER. 


The  actual  commercial  marks,  according  to  the  order  of  their 
quality,  are — 

S.  F.  for  superfine — containing  all  the  matter  of  the  root. 
S.  F.  F.  for  fine  superfine — containing  all  the  ligneous  matter 
of  the  root,  the  mull  or  bark,  or  outside  portion 
being  separated. 
E.  S.  F.  F.  for  extra  fine  fine — containing  the  heart,  or  centre  of 
the  root,  and  the  internal  part  of  the  oily  ring 
which  surrounds  it;  being  also  twice  sifted  so  as 
to  separate  completely  from  the  mull,  &c. 

These  three  varieties  may  themselves  vary  according  to  the 
nature  of  the  roots,  and  the  manner  in  which  they  are  dried, 
and  otherwise  prepared ;  but  it  is  from  these  that  all  the  va- 
rious mixtures  are  made ;  and  the  tact  of  the  manufacturers 
consists  in  mixing  them  so  as  to  produce  the  qualities  required 
by  the  consumer. 

Avignon  madder  can  be  used  fresh,  although  it  is  better  to 
be  kept  for  twelve  months.    It  does  not  cake  or  agglomerate 
in  the  cask,  but  when  kept  too  long  it  becomes  deteriorated  in 
quality,  undergoing  the  same  kind  of  decomposition  as  the 
other  madders. 

Madder  is  often  adulterated  by  mixing  with  it  brickdust, 
red  or  yellow  ochres,  sand,  and  clay,  or  by  adding  sawdust  of 
certain  woods,  as  mahogany,  logwood,  sandal-wood,  &c.  &c. 
The  mineral  adulterations  may  be  detected  by  putting  some  of 
the  suspected  madder  in  a  large  glass  vessel,  and  adding  to  it 
a  quantity  of  pure  water;  the  madder  floats,  and  the  mineral 
adulterations  sink  to  the  bottom.  We  thus  readily  obtain  an 
approximate  idea  of  the  quantity  of  adulterating  matters  pre- 
sent, and  by  carefully  removing  the  floating  madder,  and  then 
filtering  the  liquor,  the  mineral  substances  may  be  separated 
and  weighed.  We  may  also  proceed  by  burning  a  small  por- 
tion of  the  madder  and  seeing  the  ash  that  remains;  we  have 
in  this  way  tried  various  samples,  having  8J  per  cent,  of  ash. 

When  the  adulterants  consist  of  sawdust  or  other  ground 
vegetable  matters,  their  detection  is  much  more  difficult;  in- 
deed, the  only  means  likely  to  be  at  all  successful,  is  to  weigh 
a  portion  of  the  suspected  madder,  and  to  try  its  coloring  pow- 
ers by  a  piece  of  prepared  cotton;  except  where  chemical  skill 
can  be  applied,  the  coloring  matter  of  the  madder  can  be  ex- 
tracted, and  compared  with  other  known  qualities. 

Some  of  the  French  d^ers  use  a  colorimeter  for  judging  of  the 
quality  of  their  madder.  It  depends  upon  a  principle  similar 
to  that  of  Mr.  Crum's  chlorimeter  for  testing  the  strength  of 
bleaching  powder  (see  page  87).    A  weighed  quantity  of  mad- 


ALIZARIN. 


337 


der  of  known  quality  is  boiled,  and  the  decoction  is  put  into 
a  glass  vessel;  similar  quantities  of  the  madders  to  be  tried 
are  treated  in  the  same  manner,  and  placed  in  a  glass  vessel  of 
similar  size  and  form,  and  the  tint  of  color  is  judged  by  com- 
parison. Of  course,  the  test  solution  may  be  diluted  by  a 
measured  quantity  of  water,  and  by  using  a  graduated  glass, 
their  comparative  values,  estimated  by  the  rate  of  dilution,  &c, 
may  be  easily  ascertained.  But  this  method  is  subject  to  many 
errors,  as  when  any  adulteration  has  been  practised  on  the 
madder  by  addition  of  other  vegetable  coloring  matters,  such 
as  sapan-wood,  &c. 

Madder  has  been  the  subject  of  a  great  many  chemical  in- 
vestigations, the  study  of  which  is  highly  useful  to  those  who 
use  this  dye-drug  in  their  operations.*  The  first  investigation 
into  the  chemical  properties  of  madder  led  to  the  discovery  of 
two  distinct  coloring  matters — one  yellow,  which  is  very  solu- 
ble in  cold  water,  and  named  xanthin ;  the  other  red,  mode- 
rately soluble  in  hot  water,  is  called  alizarin.  Several  methods 
of  extracting  alizarin  by  sulphuric  acid  have  been  proposed, 
but  the  following  is  probably  the  most  simple  in  practice : 
"One  pound  weight  of  madder  is  mixed  up  with  an  equal 
weight  of  concentrated  sulphuric  acid,  the  vessel  so  closed  up 
that  no  heat  is  evolved,  and  allowed  to  stand  in  a  cool  place 
for  three  or  four  days ;  by  this  process  all  the  constituents  of 
the  madder  are  converted  into  charcoal,  except  the  alizarin. 
When  this  charring  process  is  completed,  the  mixture  is  care- 
fully dried,  and  then  digested  in  alcohol,  which  dissolves  the 
alizarin  and  leaves  the  charcoal.  The  solution  may  now  be 
diluted  with  water,  and  put  into  a  retort,  and  kept  at  a  heat  of 
170°  Fah. ;  the  beak  of  the  retort  being  connected  to  a  receiver, 
the  alcohol  distils  over  and  is  recovered.  Water  and  alizarin 
remain  in  the  retort,  which  being  poured  out  and  filtered,  the 
alizarin  remains  upon  the  filter  in  a  state  of  great  purity.  It 
is  of  a  beautiful  red  color,  and  gives  the  same  color  to  boiling 
water." 

Alizarin  is  soluble  in  turpentine,  naphtha,  and  fat  oils; 
chlorine  turns  it  into  a  yellow-brown  ;  sulphuric  acid  dissolves 
it,  and,  at  the  same  time  enlivens  the  color  ;  muriatic  and 
nitric  acids  both  dissolve  it,  changing  the  color  from  red  to 
yellow. 

Alkalies     .    .    .    .A  violet  color. 

Alumina     ....  A  deep  red-brown  precipitate. 

Oxides  of  tin   .    .    .  Precipitates  of  the  same  appearance. 

*  See  2d,  5th,  and  6th  vols.  Chemical  Gazette ;  1st  vol.  of  Pharmaceutical 
Times  ;  33d  vol.  Phil.  Magazine,  &c. ;  Thomson's  Vegetable  Chemistry. 

22 


338 


MADDER. 


Phosphates  have  a  very  powerful  attraction  for  alizarin,  so 
much  so,  that  when  animals  take  any  madder  into  their  system, 
the  bones,  which  contain  a  considerable  quantity  of  phosphates, 
become  colored  red.  This  fact  is  well  known  to  dyers  who 
are  in  the  habit  of  using  madder  in  their  operations,  and  neces- 
sarily often  tasting  it.  When  taken  in  quantity,  the  urine  is 
colored  by  it. 

From  the  above  reactions  of  alizarin  with  other  substances, 
it  was  supposed  that  it  constituted  the  true  coloring  of  madder ; 
and  means  were  soon  adopted  to  separate  this  coloring  matter 
from  the  vegetable,  and  use  it  pure ;  but  it  was  afterwards 
found  that  a  fixed  dye  could  not  be  obtained  by  pure  alizarin, 
and  therefore  it  did  not  constitute  all  that  was  required  in  giv- 
ing the  dye.  This  led  to  further  investigations,  productive  of 
further  discoveries  respecting  these  coloring  matters.  It  finally 
appeared  that  madder  has  five  different  coloring  matters,  which 
have  been  named — 


Madder  purple, 
Madder  red, 


Madder  orange, 
Madder  yellow, 


Madder  brown ; 

each  of  which  may  be  obtained  by  the  following  operations  : — 
Madder  Purple. — The  madder  is  washed  in  water  at  about 
summer  heat,  then  boiled  in  a  strong  solution  of  alum  for  an 
hour;  the  clear  liquor  is  afterwards  decanted,  and  sulphuric 
acid  added,  which  precipitates  the  madder  purple  along  with  a 
number  of  impurities.  These  are  removed  by  washing  with 
boiling  water,  then  with  pure  muriatic  acid,  and  afterwards 
dissolving  in  alcohol.  Madder  purple  is  soluble  in  hot  water; 
and  if  pure  it  gives  the  water  a  dark-pink  color.  If  the  water 
contains  lime,  a  great  part  of  the  coloring  matter  is  precipi- 
tated as  a  reddish-brown  substance.  Cotton,  saturated  with 
the  acetate  of  alumina,  is  dyed  a  bright  red,  provided  the 
quantity  of  madder  purple  be  not  too  great  for  the  aluminous 
base,  but  if  so,  the  color  will  have  more  of  a  purple  tint.  A 
boiling  solution  of  alum  forms  with  the  madder  purple  a 
cherry -red  solution ;  caustic  potash  forms  with  it  a  fine  yel- 
lowish red  color;  the  carbonates  of  potash  and  soda  have  a 
similar  effect ;  and  sulphuric  acid  produces  a  bright  red  or  rose 
color. 

Madder  Eed  is  separated  from  madder  purple  in  conse- 
quence of  its  not  being  soluble  in  a  strong  solution  of  alum. 
It  is  obtained  by  boiling  madder  in  a  weak  solution  of  alum, 
by  which  a  reddish-brown  precipitate  is  obtained.  This  pre- 
cipitate is  repeated  and  boiled  in  pure  muriatic  acid,  then 


COLORING-  MATTERS. 


339 


washed  carefully  with  water  and  boiled  in  alcohol.  This  dis- 
solves both  madder  red  and  madder  purple  ;  but,  by  gently 
evaporating  the  alcoholic  solution  until  it  is  very  much  con- 
centrated, and  then  allowing  it  to  cool,  an  orange-colored  pre- 
cipitate is  formed,  which  is  collected  and  repeatedly  boiled  in  a 
strong  solution  of  alum,  as  long  as  the  alum  solution  comes  off 
colored  ;  the  insoluble  portion  is  madder  red.  It  is  a  yellow- 
ish-brown powder,  and  imparts  to  cotton,  impregnated  with 
acetate  of  alumina,  a  dark-red  color,  when  in  excess;  but  if  the 
mordanted  cotton  be  in  excess,  a  brick-red  color  is  produced. 
Caustic  potash  gives  a  violet,  carbonate  of  soda  a  red,  and  sul- 
phuric acid  a  brick-red  solution. 

Madder  Orange  is  distinguished  from  the  former  two  colors 
by  its  slight  solubility  in  alcohol.  It  is  prepared  by  macera- 
ting madder  for  twenty-four  hours  in  distilled  water,  the  infu- 
sion being  strained  off  and  allowed  to  repose  a  few  hours.  The 
liquor  is  carefully  decanted  and  filtered  through  a  paper  filter, 
upon  which  the  madder  orange  remains.  It  may  be  washed 
with  cold  water,  and  afterwards  purified  by  spirits  of  wine,  in 
which  it  is  not  soluble.  It  is  a  yellow  powder,  soluble  in  boil- 
ing water,  and  imparts  to  cotton  impregnated  with  an  aluminous 
mordant  a  bright  orange  color,  when  in  excess.  A  boiling  solu- 
tion of  alum  forms  with  madder  orange  a  yellow  solution  ; 
caustic  potash  gives  a  dark  rose,  carbonate  of  soda  an  orange, 
and  sulphuric  acid  an  orange-yellow  color. 

Madder  Yellow  is  characterized  by  its  great  solubility  in 
water.  It  is  a  yellow  gummy  mass,  communicates  to  mor- 
danted cotton  a  pale-nankeen  color,  but  does  not  of  itself  form 
a  true  dye.  Madder  which  contains  much  of  this  ingredient 
is  of  inferior  quality,  as  the  yellow  becomes  so  incorporated 
with  the  other  colors  as  materially  to  deteriorate  them,  and  to 
require  several  operations  to  free  the  goods  from  it  afterwards. 

Madder  Brown  is  a  brownish-black  dry  mass,  obtained  in 
the  preparation  of  the  other  coloring  matters.  It  is  neither 
soluble  in  water  nor  alcohol,  is  of  no  importance  as  a  dye-drug, 
and  does  not  enter  into  any  of  the  colors  dyed  by  madder. 

'  Madder  Acids. — Besides  these  five  coloring  matters,  mad- 
der contains  two  acid  substances,  named  madderic  and  rubiacic 
acids.  They  have  no  known  dyeing  properties,  and  are, only 
mentioned  here  to  show  the  intimate  knowledge  which  chemists 
possess  of  this  agent.  Indeed,  so  important  were  any  investiga- 
tions in  madder  considered,  that  the  Societe  Industrielle  de 
Mulhouse  for  several  years  offered  2000  francs  as  a  premium 
for  the  best  analytical  investigation  of  this  substance. 

Useful  Products. — It  will  be  observed  in  this  brief  outline 
of  the  coloring  matters  of  madder,  that  only  three  of  them  are 


340 


MADDER. 


of  importance  to  the  dyer,  viz.,  the  red,  purple,  and  orange.  It 
will  also  be  observed  that  these  three  coloring  substances  have 
a  similarity  of  action  towards  mordanted  cottons.  Taken  singly, 
not  one  of  them  forms  a  good  dye  ;  but  they  constitute  the 
elements  which  together  produce  the  richest  and  most  perma- 
nent reds  which  the  modern  dyer  possesses.  Indeed,  prac- 
tically, it  is  only  necessary  to  consider  madder  as  containing 
no  more  than  two  coloring  matters,  as  was  formerly  supposed ; 
viz.,  the  dun,  or  yellow,  which  constitutes  the  impurity  of  the 
madder,  and  which  the  dyer  endeavors  to  get  rid  of,  and  the 
red-coloring  matter.  The  former,  or  yellow,  does  not  combine 
with  the  cloth  alone,  and  probably  not  at  all;  but  it  has  a 
strong  affinity  for  the  other  coloring  matters,  and  combines 
with  them  when  they  are  upon  the  cloth,  and  has  to  be  sepa- 
rated from  them  by  after  processes.  The  latter,  or  red,  which 
is  a  combination  of  all  the  three,  the  red,  the  purple,  and  the 
orange,  unites  with  the  cotton  as  one,  and  is  known  to  the  dyer 
only  in  the  aggregate  state.  This  coloring  matter  is  difficultly 
soluble  in  water,  and  therefore  no  strong  decoction  of  it  can 
be  obtained  by  boiling,  so  that  it  is  not  very  applicable  for 
compound  colors,  and  therefore  of  little  avail  in  the  fancy  dye- 
house.  Many  extensive  fancy  dyers,  indeed,  do  not  consider 
madder  as  even  belonging  to  their  province.  They  use  it  very 
seldom,  except  to  give  a  peculiar  tint  to  some  light  compound 
colors,  and  for  fast  salmon  colors,  pinks,  &c.  When  deep  colors 
are  to  be  dyed  by  madder,  the  goods  must  be  put  into  the  dye- 
bath  or  boiler  along  with  the  madder,  in  a  way  nearly  similar 
to  that  described  for  barwood. 

Madder  in  the  hands  of  the  skilful  operator  can  be  made  to 
produce  a  vast  variety  of  colors  and  tints,  by  corresponding 
changes  of  his  mordants,  and  the  colors  are  all  characterized 
by  a  degree  of  permanency  which  no  other  vegetable  dyewrood 
produces.  The  operations,  however,  are  generally  much  more 
tedious  than  those  for  ordinary  fancy  colors ;  and  much  skill 
is  also  required  in  preparing  and  applying  the  proper  mordants 
for  madder  colors,  and  also  in  the  preparation  of  the  cloths  for 
the  different  mordants. 

Madder  Preparations. — There  are  two  coloring  substances 
prepared  from  madder,  which  are  now  being  much  used  in  dye- 
ing and  calico  printing,  and  which  seem  to  embrace  all  those 
different  coloring  principles  we  have  been  describing ;  these  are 
garancine  and  colorine.  The  former  was  first  formed  and  de- 
scribed by  MM.  Eobiquet  and  Colin,  as  far  back  as  1828 ;  but 
it  was  long  before  it  was  introduced  generally  to\he  trade. 
Garancine  is  a  chocolate-colored  powder  having  no  taste  or 
smell ;  but  from  differences  in  the  modes  of  preparation,  and 


MADDER  PREPARATIONS. 


341 


also  in  the  qualities  of  the  madders  from  which  it  is  prepared, 
it  varies  very  much  in  quality,  which  is  probably  the  reason 
why  it  has  been  repeatedly  taken  up  and  abandoned  by  dyers. 
Ultimately,  however,  means  of  testing  its  quality,  &c,  were 
devised,  and  have  proved  favorable  to  its  more  constant  em- 
ployment. The  manner  of  forming  garancine,  as  given  by 
MM.  Eobiquet  and  Colin,  is  to  take  one  part  of  madder,  and 
five  or  six  parts  of  cold  water,  and  allow  the  mixture  to  mace- 
rate till  the  following  day ;  the  whole  is  then  thrown  upon  a 
cloth-filter,  and  when  drained  is  subjected  to  pressure.  It  is 
then  to  be  steeped  again  in  cold  water  and  pressed,  and  so  on 
for  the  third  time.  When  these  operations  are  completed, 
almost  half  as  much  sulphuric  acid  (by  weight)  as  there  was 
of  the  madder  in  its  first  state,  is  to  be  diluted  with  water,  so 
as  to  raise  the  temperature  as  much  as  possible,  and  this  is 
added  to  the  pressed  madder  while  hot,  and  stirred  as  rapidly 
as  possible ;  the  temperature  is  then  raised  and  kept  at  212° 
for  about  an  hour.  A  quantity  of  water  is  then  added,  and 
the  whole  is  thrown  upon  a  filter ;  water  is  poured  over  the 
residue  until  it  passes  through  the  filter  without  taste  of  acid, 
and  the  matter  collected  is  then  pressed  and  dried,  and  passed 
through  a  sieve.  This  constitutes  garancine.  The  sulphuric 
acid  used  is  not  altered  in  character,  but  seems  only  to  have 
carbonized  some  of  the  impurities  in  the  roots,  without  affect- 
ing the  red-coloring  matter.  There  are  several  other  methods 
of  preparing  the  substance,  but  not  differing  essentially  from 
that  described;  as  throwing  the  rough  madder  into  water,  and 
heating  it  to  the  boiling  point,  then  adding  the  sulphuric  acid, 
after  which  the  whole  is  filtered,  washed,  and  dried,  and  reduced 
to  powder,  &c.  During  the  last  few  years  the  consumption, 
and  consequently  the  manufacture  of  garancine,  has  greatly  in- 
creased. The  mode  of  testing  garancine  is  similar  to  that 
described  for  madders;  either  by  the  depth  of  dye  produced 
on  mordanted  cotton,  or  by  means  of  the  colorimeter.  In 
1843,  a  patent  was  taken  for  extracting  garancine  from  the 
waste  madders  of  the  dye-house,  and  we  believe  has  been  pro- 
ductive of  great  saving  and  advantage.  The  substance  of  the 
process  thus  patented  is: — 

"The  invention  consists  in  manufacturing  a  certain  coloring 
matter  called  garancine  from  refuse  madder,  or  madder  which 
has  been  previously  used  in  dyeing,  such  madder  having 
ordinarily  been  thrown  away  as  spent  and  of  no  value,  and  the 
said  coloring  matter  called  garancine  having  been  produced 
heretofore  from  fresh  or  unused  madder.  A  large  filter  is 
constructed  outside  the  building  in  which  the  dye-vessels  are 
situated,  formed  by  sinking  a  hole  in  the  ground,  and  lining 


342 


MADDER. 


it  at  the  bottom  and  sides  with  bricks  without  any  mortar  to 
unite  them.  A  quantity  of  stones  or  gravel  is  placed  upon 
the  bricks,  and  over  the  stones  or  gravel  common  wrappering, 
such  as  is  used  for  sacks.  Below  the  bricks  is  a  drain  to  take 
off  the  water  which  passes  through  the  filter.  In  a  tub  adjoin- 
ing the  filter  is  kept  a  quantity  of  dilute  sulphuric  acid,  of 
about  the  specific  gravity  of  one  hundred  and  five,  water  being 
one  hundred.  Hydrochloric  acid  will  answer  the  several  pur- 
poses, but  sulphuric  acid  is  preferred  as  more  economical.  A 
channel  is  made  from  the  dye- vessels  to  the  filter.  The  madder 
which  has  been  employed  in  dyeing  is  run  from  the  dye-vessels 
to  the  filter ;  and  while  it  is  so  running,  such  a  portion  of  the 
dilute  sulphuric  acid  is  run  in  and  mixed  with  it  as  changes 
the  color  of  the  solution  and  the  undissolved  madder  to  an 
orange  tint  or  hue.  This  acid  precipitates  the  coloring  matter 
which  is  held  in  solution,  and  prevents  the  undissolved  madder 
from  fermenting  or  otherwise  decomposing.  When  the  water 
has  drained  from  the  madder  through  the  filter,  the  residuum 
is  taken  from  off  the  filter  and  put  into  bags.  The  bags  are 
then  placed  in  an  hydraulic  press  to  have  as  much  water  as 
possible  expressed  from  their  contents.  In  order  to  break  the 
lumps  which  have  been  formed  by  compression,  the  madder  or 
residuum  is  passed  through  a  sieve.  To  5  cwt.  of  madder  in 
this  state,  placed  in  a  wood  or  lead  cistern,  1  cwt.  of  sulphuric 
acid  of  commerce  is  sprinkled  on  the  madder,  through  a  lead 
vessel  similar  in  form  to  the  ordinary  watering-can  used  by 
gardeners.  An  instrument  like  a  garden  spade  or  rake  is  next 
used,  to  work  the  madder  about  so  as  to  mix  it  intimately  with 
the  acid.  In  this  stage,  the  madder  is  placed  upon  a  perforated 
lead-plate,  which  is  fixed  about  five  or  six  inches  above  the 
bottom  of  the  vessel.  Between  this  plate  and  the  bottom  of 
the  vessel  is  introduced  a  current  of  steam  by  a  pipe,  so 
that  it  passes  through  the  perforated  plate  and  the  madder 
which  is  upon  it.  During  this  process,  which  occupies  from 
one  to  two  hours,  a  substance  is  produced  of  a  dark-brown 
color  approaching  to  black.  This  substance  is  garancine  and 
insoluble  carbonized  matter.  When  cool,  it  is  placed  upon  a 
filter  and  washed  with  clear  cold  water  until  the  water  passes 
from  it  without  an  acid  taste.  It  is  then  put  into  bags  and 
pressed  with  an  hydraulic  press.  The  substance  is  dried  in  a 
stove  and  ground  to  a  fine  powder  under  ordinary  madder- 
stones,  and  afterwards  passed  through  a  sieve.  In  order  to 
neutralize  any  acid  that  may  remain,  from  four  to  five  pounds 
of  dry  carbonate  of  soda  for  every  hundred  weight  of  this  sub- 
stance is  added  and  intimately  mixed.  The  garancine  in  this 
state  is  ready  for  use."    Sealed,  August  8,  1843. 


COLORINE. 


343 


The  following  is  the  action  of  garancine  when  put  into  dif- 
ferent qualities  of  water  and  with  reagents:  — 

Distilled  water,  cold  ...  A  pale  yellow  in  about  24  hours. 
Distilled  water,  boiling  .  .  A  pale  reddish-yellow  tint. 
Spring  water,  cold  ....  Less  colored  than  with  cold  distilled 

water. 

Boiling  spring  water    .  .  Less  colored  than  with  boiling  dis- 
tilled water. 

Cold  lime-water    ....  Paler  than  with  either  cold  distilled 

or  spring  water. 
Water  with  a  little  sul-  )    Greenish-yellow   tint  after  some 

phuric  acid     ...     J  hours. 
Water  with  H  CI  .  .  .  .  The  same,  but  darker  in  tint. 
Water  with  NO5  ....  Still  darker  tint,  passing   into  a 

brownish-blue. 
Water  with  acetic  acid    .  Faintly  yellow. 
Strong  acetic  acid  ....  Acquires  a  beautiful  reddish-yellow 

color. 

f   Becomes  red  immediately,  and  after 


Cold  alum  water  ....  Chrome-red  color. 
Boiling  alum  water  ...  A  dark-red  color. 

The  mordants  used  for  dyeing  with  garancine  are  the  same 
as  for  dyeing  with  madder.  It  only  yields  its  color  to  the 
mordanted  cloth  at  a  boiling  temperature,  and  the  water  of  the 
bath  or  boiler  does  not  become  colored.  A  little  sumach  is 
often  used  along  with  the  garancine  for  reds. 

If  the  water  used  in  dyeing  be  a  calcareous  spring,  a  little 
sulphuric  acid,  just  enough  to  give  the  water  a  sour  taste, 
should  be  added;  but  when  sumach  is  used,  the  acid  is  not  re- 
quired. The  dye  obtained  by  garancine  is  generally  more 
brilliant  and  lively  than  from  madder.  In  printing,  the  color 
is  not  so  liable  to  run  upon  the  white,  and  the  goods  are  con- 
sequently more  easily  cleared  that  when  madder  is  used. 

Colorine  is  the  residue  left  by  distilling  the  alcoholic  tinc- 
ture made  by  treating  garancine  with  spirits  of  wine.  It  is 
considered  to  be  impure  alizarine.  When  this  product  is  taken 
from  the  retort,  it  is  in  the  form  of  an  extract;  but  diluted 
with  water,  separated,  subjected  to  pressure,  and  then  dried  and 


Water  with  ammonia 


Ammonia 


a  few  hours  so  deep  as  not  to  be 
transparent. 
Beautiful  red  color. 


Dark  red-brown. 


Bright  reddish  color. 


344 


MADDER. 


pulverized,  it  resembles  yellow  ochre.  It  leaves  a  deep  stain 
on  the  fingers  if  moistened  by  it.  It  is  prepared  in  France  at 
a  cheap  rate,  and  used  in  calico  printing  by  being  dissolved  in 
ammonia,  thickened  with  gum,  and  applied  to  the  cloth  pre- 
viously mordanted. 

The  mordants  used  for  madder  and  the  coloring  preparations 
obtained  from  it,  are  the  acetate  of  alumina,  acetate  of  iron,  and 
mixtures  of  these;  the  chlorides  of  tin,  acetate  of  lead,  and 
acetate  of  copper,  and  sometimes  ammoniuret  of  copper.  The 
last  two  are  often  used  as  alterants.  In  using  iron  mordants  it 
is  of  the  utmost  consequence  that  they  be  the  proto-salts  ; 
hence,  iron  liquor  is  more  frequently  used  than  sulphate  of 
iron,  which  salt  is  more  apt  to  become  peroxidized. 

In  dyeing  with  madder,  there  are  many  operations  not  prac- 
tised in  the  fancy  dye-house,  such  as  dunging,  &c. 

Coloring  Principles  of  Madder. — The  true  composition 
of  the  coloring  substances  contained  in  madder  has  been  more 
recently  a  subject  of  study  by  many  chemists.  Dr.  Schunck 
calls  rubian  the  coloring  principle  of  madder,  which,  under  the 
action  of  a  special  ferment  named  erythrozym,  or  of  acids  or 
alkalies,  would  be  converted  into  alizarine  by  losing  water. 
Thus:— 

Rubian.  Alizarine. 


Ci6H34O30    -    4  (C14H504)  +  14  HO. 

The  xanthine  of  Mr.  Kuhlmann  was  the  yellow  coloring  prin- 
ciple of  madder,  which,  under  the  influence  of  the  atmosphere, 
produced  the  various  coloring  substances  extracted  from  this 
root. 

Mr.  Decaisne,  when  examining  under  the  microscope  the  cel- 
lular tissue  of  madder,  found  that  when  the  root  was  fresh,  the 
coloring  matter  contained  in  it  was  yellow,  but  turned  red  by 
exposure  to  the  air,  and  that  old  roots  presented  also  the  red 
coloration.  This  experiment  exhibits  a  coloring  principle 
which  may  be  transformed  into  different  colors  by  oxidation, 
and  by  different  chemical  operations. 

Mr.  P.  Schiitzenberger,  working  with  the  pure  products,  ob- 
tained from  madder  by  the  process  of  Mr.  E.  Kopp,  found  the 
following  substances : — 

2*  Pu^urhie  1     Which  are  red,  or  orange  red,  and 

o     urP^rme?      .       (  dye  red  with  alumina  mordants. 

3.  Pseudo-purpunne.   )  J 

4.  An  orange  substance,  which  dyes  red  with  mordants  of 
alumina. 

5.  A  yellow  substance  {Xanthopurpurine),  distinct  from  xan- 
thine, and  which  dyes  yellow  with  mordants  of  alumina. 


COLORING  PRINCIPLES  OF  MADDER.  845 

Alizarine  gives  with  alkalies  a  violet  solution,  and  is  nearly 
insoluble  in  a  boilinsr  solution  of  alum. 

o 

Purpurine  gives  with  alkalies  a  red  solution,  which  does  not 
stand  exposure  to  the  atmosphere.  It  is  also  very  soluble  in  an 
alum  solution,  which  becomes  pink. 

Some  years  ago,  Mr.  B.  Kopp  produced  alizarine  by  sublima- 
tion, by  means  of  superheated  steam  passing  through  pulver- 
ized madder.  Another  process  by  the  same  chemist,  and 
employed  with  advantage  by  Messrs.  Shaaff  and  Lauth,  of  Stras- 
bourg, consists  in  macerating  madder  for  several  hours  in  a 
solution  of  sulphurous  acid.  After  maceration,  the  liquors  are 
acidulated  with  sulphuric  acid,  and  heated  to  about  100°  or 
110°  Fahr.,  when  purpurine  precipitates.  The  liquors  being 
then  made  to  boil  for  several  hours,  green  alizarine  is  also 
precipitated.  The  green  coloring  matter  may  be  removed  by 
treatment  with  15  to  20  times  its  weight  of  petroleum,  and  12 
per  cent,  of  a  solution  of  caustic  soda  (1  part  soda  for  12  of 
water).  After  saturation  by  sulphuric  acid,  the  yellow  aliza- 
rine is  collected,  and  is  ready  for  use  for  printing  steam  colors. 

Green  alizarine  is  as  good  as  commercial  alizarine,  better  than 
the  flowers  of  madder,  and  requires  ten  per  cent,  less  mordant 
than  when  the  latter  are  employed.  It  should  be  wetted  with 
boiling  water  before  using,  otherwise  it  will  swim  on  top  of 
the  bath.    Calcareous  waters  are  to  be  avoided. 

The  purpurine  is  equal  in  coloring  power  to  sixty  times  its  own 
weight  of  powdered  madder,  is  soluble  in  ammonia,  acetic  acid, 
alkaline  carbonates,  and  even  water. 

When  used  for  dyeing  silk,  it  is  well  to  neutralize  it  with 
about  1  per  cent,  of  chalk  or  carbonate  of  soda.  The  cotton 
yarns  are  to  be  mordanted  as  usual,  with  the  addition  of  a  little 
tannin. 

For  calico  printing,  the  paste  is  made  of  f  oz.  purpurine  in 
one  quart  of  water,  and  20  per  cent,  of  carbonate  of  soda.  The 
whole  is  boiled,  filtered,  and  thickened. 

For  wool  dyeing,  the  stuff  is  mordanted  with  alum  and  cream 
pf  tartar;  or  tartar  and.  oxymuriate  of  tin  prepared  as  follows  : — 

300  parts  nitric  acid  ; 
100     "    water ; 

50     "    sal  ammoniac  ;  and 

50     "    tin  gradually  added  to  the  cold  liquid. 

This  solution  is  allowed  to  rest  several  days,  and  is  filtered 
before  it  is  ready  for  use.  The  mordanted  wool  is  then  dyed 
in  a  solution  of  purpurine,  beginning  at  a  temperature  of  86°, 
and  raising  afterwards  to  the  boiling  point. 

With  cream  of  tartar  and  tin  for  mordants,  the  color  is  a  scarlet 


346 


MADDER. 


red,  nearly  as  fine  as  that  from  cochineal.  Alum  and  cream  of 
tartar  give  a  crimson  red.  For  red  orange,  add  to  the  above 
mordants  some  fustic  or  Cuba  wood,  heat  the  whole  in  a  tinned 
kettle,  and  then  dye  with  purpurine. 

For  silk  printing,  the  stuff  is  mordanted  with  acetate  of  alu- 
mina (5°  B.),  with  a  little  chalk  added  to  the  water,  dried,  and 
passed  through  a  weak  solution  of  gum  tragacanth  (|  oz.  per 
quart).  The  printing  paste  is  made  with  1J  oz.  purpurine  per 
quart  of  water,  and  J  oz.  of  soda  crystals.  After  filtration  add 
J  lb.  roasted  starch,  heat  the  whole,  and  print  with  it  when 
cold.  The  cloth  is  then  steamed,  washed,  passed  through 
soap,  &c. 

Purpurine  does  not  give  purples  with  iron  mordants. 

The  madder  left  as  residue,  after  the  treatment  by  sulphu- 
rous acid,  may  be  transformed  into  garancine,  but  its  dyeing 
power  is  only  one-half  that  of  ordinary  garancine. 

Flowers  of  Madder. — This  product,  introduced  into  the  trade  by 
Messrs.  Julian  and  Roquer,  consists  of  madder,  which,  by  fermen- 
tation, has  been  deprived  of  most  of  its  mucilaginous  and  sac- 
charine matters.  The  extra  expense  of  this  process  is  more 
than  paid  by  the  alcohol  resulting  from  the  fermentation,  and 
the  increased  coloring  power  of  madder  flowers,  which  is  double 
that  of  common  madder. 

Commercial  Alizarine  or  Pincoffineis  due  to  Messrs.  Schunck  and 
Pincoffs,  of  Manchester.  It  is  a  garancine,  entirely  free  from 
acid,  and  which  has  been  submitted  to  high  pressure  or  super- 
heated steam.  The  substances  which  interfere  with  the  purple 
dyeing  properties  of  alizarine  are  destroyed  or  modified  by  the 
process.  This  commercial  alizarine,  gives  a  beautiful  violet 
with  calcareous  waters,  and  no  raising  is  required. 

Tests  for  Madder. — Madder  is  frequently  adulterated  with 
foreign  substances,  which  have  been  found  to  consist  of: — 

I.  Brick-dust,  sand,  ochre,  and  clay  ; 

II.  Saw  dust  from  oakwood  and  mahogany,  bran,  and  pow- 
dered logwood,  sapan,  Brazil  wood,  &c. 

The  impurities  of  the  first  class  are  easily  detected  by  the 
calcination  of  a  certain  amount  of  the  suspected  powder.  Pure 
and  well  prepared  madder  does  not  contain  more  than  5  per  cent, 
of  ashes.  Some  sorts,  which  have  not  been  prepared  very 
carefully,  may  give  9  per  cent,  of  ashes.  But  above  this  latter 
proportion,  all  excess  of  ashes  results  from  a  fraudulent  mix- 
ture. The  sample  on  trial  ought  to  have  been  well  desiccated 
at  212°  Fahr.,  because  the  proportion  of  water  in  madder  is 
also  exceedingly  variable. 

The  adulterations  of  the  second  class  are  not  so  easily  detect- 
ed.   Mr.  Pernod,  of  Avignon,  has  proposed  the  following  rapid 


TESTS  FOR  MADDER. 


347 


process:  A  sheet  of  white  paper,  six  inches  square,  is  dipped 
for  one  minute  into  a  weak  solution  of  bichloride  of  tin,  put 
afterwards  upon  a  glass  or  porcelain  slab,  and  covered  by  means 
of  a  sieve  with  the  madder  on  trial.  After  one-half  hour,  the 
paper  will  show  at  the  places  touched  by  the  foreign  matters  : — 

Crimson-red  points  with  Brazil  wood  ; 

Purple  spots  with  logwood  ; 

A  yellow  coloration  with  Lima  or  Cuba  woods;  while 
Madder  produces  a  very  light  yellow. 

For  discovering  the  tannin  of  oak  and  bark,  another  paper 
is  impregnated  with  an  old  solution  of  copperas,  dried,  and 
then  wetted  with  alcohol.  If  there  are  substances  holding  tannin, 
the  paper,  after  15  minutes,  shows  blue-black  spots,  while  mad- 
der stains  only  a  light-brown. 

Good  flowers  of  madder  impart  scarcely  any  coloration  to 
the  distilled  water  in  which  they  have  been  allowed  to  macerate. 
The  filtered  water  is  neutral  to  the  test  papers,  does  not  precipi- 
tate by  nitrate  of  baryta,  becomes  slightly  pink-colored  when 
heated  with  oil  of  vitriol,  and  turns  yellowish  by  hydrochloric 
acid. 

When  the  flowers  of  madder  are  of  a  bad  quality,  the  water 
is  colored  and  acid,  gives  a  precipitate  by  nitrate  of  baryta, 
and  becomes  green  after  heating  with  sulphuric  or  muriatic 
acids. 

All  these  processes,  while  they  permit  the  detection  of  fraudu- 
lent impurities,  do  not  indicate  the  coloring  power  of  madder. 
For  this  latter  purpose,  the  only  effective  way  consists  in  dyeing 
several  pieces  of  calico  of  the  same  size,  mordanted  with  one 
or  several  mordants,  and  comparing  the  result  with  that  of  a 
madder  of  good  quality.  The  operation  is  performed  in  glass 
vessels  heated  over  a  water  bath,  the  temperature  of  which  is 
slowly  raised  from  85°  to  167°  Fahr.,  during  one  hour  and  a 
half,  and  then  rapidly  carried  up  to  the  boiling  point,  which  is 
kept  on  for  15  minutes.  The  calico  samples,  which  have  been 
constantly  stirred  in  order  to  dye  them  evenly,  are  rinsed  in 
'  cold  water  and  dried. 

The  samples  are  then  cut  in  two.  One  half  is  retained,  and 
the  other  is  submitted  to  the  following  operations :  A  passage  in 
a  solution  of  bleaching  powder  (J  of  1  degree  B.),  at  the  tem- 
perature of  95°,  during  five  minutes;  two  washings,  each 
of  5  minutes,  in  weak  soapsuds,  heated  at  100°  and  120° ; 
rinsing  in  clear  water ;  a  raising  in  weak  soapsuds  with  some 
bichloride  of  tin  ;  and.  lastly  another  passage  in  a  soap  bath, 
whose  temperature  of  140°  is  raised  to  212°.  After  washing, 
rinsing,  and  drying,  the  samples  are  compared. 

These  numerous  and  somewhat  tedious  operations  are  neces- 


348 


MUNJEET — ANNOTTA. 


sary  to  obtain  a  true  knowledge  of  the  coloring  power  and 
quality  of  the  madder.  Indeed,  this  substance  will  stand  all 
these  operations,  while  the  impurities  will  not. 

Calcareous  waters  were  thought  to  impart  certain  qualities  to 
the  dyed  products  of  certain  localities  ;  on  the  other  hand  they 
were  accused  of  doing  harm.  Purpurine  is  not  affected  by 
lime,  while  alizarine  may  be  precipitated  by  it.  These  two 
opinions  are  correct  to  a  certain  point,  when  we  come  to  con- 
sider the  nature  of  the  various  kinds  of  madder,  and  products 
of  madder,  used  in  the  arts.  The  madders  from  Holland  and 
Alsace,  grown  in  argillaceous  soils,  have  generally  an  acid  re- 
action, which  requires  a  certain  quantity  of  base,  lime,  or  soda, 
to  be  neutralized.  The  madders  from  Avignon,  on  the  con- 
trary, are  grown  in  calcareous  soils,  are  perfectly  neutral,  and 
an  excess  of  lime  would  be  rather  prejudicial.  The  same  rea- 
soning will  apply  to  certain  commercial  products  of  madder 
which,  like  the  garancine,  often  contain  an  excess  of  acid.  In 
such  cases,  calcareous  waters  are  useful. 

Munjeet 

Has  been  tried  as  a  substitute  for  madder.  It  contains  more 
coloring  matter,  and  is  found  in  commerce  in  bundles  consist- 
ing generally  of  thick  and  thin  stalks;  the  thin-stalked  variety 
contains  less  coloring  matter  than  the  thick,  and  has  the  bark 
on  ;  whereas  the  thick  stalks  are  barked.  The  stalks  of  the 
munjeet  are  very  dry,  light,  and  porous;  the  fracture  exhibits 
a  congeries  of  empty  tubes.  The  powdered  munjeet  is  com- 
posed of  the  thin  and  thick  stalks  mixed. 

Eeds  dyed  with  munjeet  are  very  brilliant,  but  fugitive,  being 
destroyed  by  a  short  exposure  to  light  and  air.  This  vegetable 
cannot,  therefore,  be  a  proper  substitute  for  madder. 

Annotta,  or  Arnotto. 

This  substance,  the  Roucou  of  the  French  dyers,  is  obtained 
from  a  shrub  originally  a  native  of  South  America,  and  now 
cultivated  in  Guiana,  St.  Domingo,  and  the  East  Indies.  1  It  is 
termed  the  annotta- tree,  or  bixa  orellana,  and  seldom  exceeds 
twelve  feet  in  height.  The  leaves  are  divided  by  fibres  of  a 
reddish-brown  color,  and  are  four  inches  long,  broad  at  the 
base,  and  tending  to  a  sharp  point.  The  stem  has  likewise 
fibres,  which  in  Jamaica  are  converted  into  serviceable  ropes. 

uThe  tree  produces  oblong  bristled  pods,  somewhat  resem- 
bling those  of  a  chestnut.    These  are  at  first  of  a  beautiful  rose 


ANNOTTA,  OR  ARNOTTO. 


349 


color,  but,  as  they  ripen,  change  to  a  dark-brown,  and  bursting 
open,  display  a  splendid  crimson  or  farina  pulp,  in  which  are 
contained  from  thirty  to  forty  seeds,  somewhat  resembling 
raisin-stones.  As  soon  as  they  arrive  at  maturity  these  pods 
are  gathered,  divested  of  their  husks,  and  bruised.  Their  pulpy 
substance,  which  seems  to  be  the  only  part  which  constitutes 
the  dye,  is  then  put  into  a  cistern,  with  just  enough  water  to 
cover  it,  and  in  this  situation  it  remains  for  seven  or  eight  days, 
or  until  the  liquor  begins  to  ferment,  which,  however,  may 
require  as  many  weeks,  according  to  circumstances.  It  is  then 
strongly  agitated  with  wooden  paddles  or  beaters  to  promote 
the  separation  of  the  pulp  from  the  seeds.  This  operation  is 
continued  until  these  have  no  longer  any  of  the  coloring  matter 
adhering  to  them;  it  is  then  passed  through  a  sieve,  and  after- 
wards boiled,  the  coloring  matter  being  thrown  to  the  surface 
in  the  form  of  scum,  or  otherwise  allowed  to  subside;  in  either 
case,  it  is  boiled  in  coppers  till  reduced  to  a  paste,  when  it  is 
made  up  into  cakes  and  dried."* 

Another  and  more  preferable  mode  of  extracting  the  color- 
ing matter  from  these  seeds,  is  by  rubbing  them  one  against 
another  under  water,  so  that  the  mucilaginous  and  other  impure 
matters  contained  in  the  interior  of  the  seed  are  not  mixed  in 
it.  The  coloring  matter  is  allowed  to  settle,  the  water  drawn 
off,  and  the  annotta  left  to  dry.  When  prepared  in  this  manner, 
it  has  a  fatty  feel,  is  very  homogeneous,  and  of  a  deep-red 
color,  which  changes  to  dark-brown  by  drying.  It  has  no 
taste,  but  generally  a  disagreeable  smell,  when  brought  into 
commerce.  This  smell,  however,  is  not  natural,  but  is  owing 
to  stale  urine  having  been  added  to  it,  in  order  to  improve  its 
color,  and  keep  it  moist. 

The  Carribee  Indians  prepare  the  annotta,  which  they  em- 
ploy for  painting  their  bodies,  by  smearing  their  hands  with 
oil,  and  then  rubbing  the  seeds  until  the  pulp  is  separated 
under  the  form  of  a  paste,  which  adheres  to  their  fingers,  and 
which  they  remove  with  a  knife  and  dry  in  the  sun. 

Annotta  of  good  quality  is  of  a  lively  red  color  when  just 
taken  from  the  seeds,  and  before  it  has  undergone  any  change. 
It  was  found  by  Mr.  John  to  contain  the  following  ingre- 
dients:— 


*  Annales  de  Chimie,  tome  47. 


350 


ANNOTTA,  OR  ARNOTTO. 


Coloring  and  resinous  matters    .    .    .  . 

Vegetable  gluten   

Lignine  

Extractive  coloring  matter  

Matter  resembling  gluten  and  extractive  . 
Aromatic  and  acidulous  matters     .    .  . 


28.0 
26.5 
20.0 
20.0 
4.0 
1.5 


100.0 


Boiling  water  dissolves  annotta,  giving  a  thick  decoction  of 
a  yellow  color.  Alkalies  form  with  it  a  white  precipitate,  giving 
the  liquor  a  clear  orange  color,  which  acids  make  redder. 

Muriatic  acid  has  no  action  upon  annotta;  chlorine  destroys 
its  color.  Nitric  acid  completely  decomposes  it,  forming  several 
compounds,  which  have  not  yet  been  sufficiently  examined. 
Sulphuric  acid  poured  upon  solid  annotta  gives  it  a  deep-blue 
color,  not  unlike  indigo,  but  it  soon  changes  to  a  dark  dirty- 
green,  and  then  to  a  darkish-purple. 

The  coloring  matters  of  annotta  are  easily  soluble  in  alka- 
lies, and  in  this  condition  they  are  generally  used  in  the  dye- 
house.  The  alkali  used  is  either  carbonate  of  soda  or  potash; 
and  when  light  shades  upon  silks  and  fine  cottons  are  wanted, 
soft  soap  is  used.  Sometimes  a  quantity  of  annotta  is  prepared 
and  kept  as  a  stock  liquor;  but  the  practice  is  bad,  as  the 
liquor  soon  becomes  stale,  and  loses  a  great  portion  of  its  dye- 
ing properties.  It  is  best  when  newly  prepared.  A  good 
method  of  preparation  is  the  following:  Into  a  boiler,  capable 
of  containing  10  to  12  gallons  of  water,  are  put  10  pounds' 
weight  of  annotta,  2  lbs.  of  carbonate  of  soda,  and  2  lbs.  of 
soft  soap,  and  the  mixture  is  boiled  until  the  annotta  is  all  dis- 
solved. 

Cloth  put  into  this  solution  is  dyed  a  dark  orange  ;  but  every 
shade,  from  an  orange  to  a  cream  color,  can  be  dyed  with  it, 
by  merely  using  it  in  a  proper  state  of  dilution  with  water. 
The  cloth  requires  no  previous  preparation  ;  but  for  fine  light 
shades  the  color  is  improved  by  dissolving  a  little  white  soap 
in  the  water  used  for  diluting  it.  The  goods  are  merely  passed 
through  the  solution,  and  dried  from  it;  but  where  the  color 
is  strong,  the  cloth  must  be  washed  in  water  containing  a  little 
soap,  to  free  it  from  the  strong  alkali  in  the  coloring  solution. 
The  addition  of  acids  turns  the  color  of  cloths  dyed  by  annotta 
to  a  yellowish-red,  so  that  by  passing  a  piece  of  cloth  dyed 
orange  through  water,  slightly  acidulated,  it  assumes  a  scarlet 
or  salmon  color,  according  to  the  quantity  of  coloring  matter 
used.  But  all  the  colors  dyed  by  annotta  are  exceedingly  fugi- 
tive, and  although  neither  acids  nor  alkalies  can  completely  re- 
move the  colors  dyed  by  it,  still,  they  are  constantly  changing 


AXNOTTA,  OR  ARNOTTO. 


851 


and  fading  by  exposure  to  the  air  and  light.  On  this  account 
annotta  is  now  very  seldom  used  in  the  cotton  dye-house,  and 
then  it  is  used  only  as  an  auxiliary.  It  is,  however,  still  used 
for  silks  and  woollens,  as  the  objections  to  its  use  for  cotton  do 
not  apply  so  strongly  in  its  relations  to  those  substances.  It 
may  also  be  used  with  propriety  for  mixed  fabrics,  such  as 
silk  and  cotton,  silk  and  woollens,  &c. 

Annotta  was  considered  to  contain  two  distinct  coloring  mat- 
ters, a  yellow  and  red,  till  it  was  shown  by  M.  Preisser  that 
the  one  is  the  oxide  of  the  other,  and  that  they  may  be  obtained 
by  adding  a  salt  of  lead  to  a  solution  of  annotta,  which  precipi- 
tates the  coloring  matter.  The  lead  is  separated  by  sulphuret- 
ed  hydrogen;  and  the  substance  being  filtered  and  evaporated, 
the  coloring  matter  is  deposited  in  small  crystals  of  a  yellow- 
white  color.  These  crystals  consist  of  bixine;  they  become  yel- 
low by  exposure  to  the  air,  but  by  dissolving  them  in  water 
this  change  is  prevented. 

Sulphuric  acid  gives  ...  A  yellow,  which  does  not  turn 


When  ammonia  is  added  to  bixine  with  free  contact  of  air, 
there  is  formed  a  fine  deep-red  color,  like  annotta,  and  a  new 
substance  is  produced,  termed  bixeine,  which  does  not  crystallize, 
but  may  be  obtained  as  a  red  powder ;  this  is  colored  blue  by 
sulphuric  acid,  and  combines  with  alkalies,  and  is  bixine  with 
addition  of  oxygen.  When  annotta,  in  the  form  of  paste,  is 
mixed  from  time  to  time  with  stale  urine  for  its  improvement, 
it  is  more  than  probable  that  this  improvement  consists  in  the 
formation  of  bixeine  from  the  bixine,  by  the  ammonia  of  the 
urine.  This  is  rendered  the  more  probable  by  finding  the  inte- 
rior of  the  annotta  yellow,  while  the  red  color  is  much  more 
developed  upon  the  surface  where  the  air  has  free  access  to  it. 
This  naturally  suggests  the  mixing  of  annotta  with  a  little 
ammonia,  and  exposing  it  to  the  air  as  much  as  possible  pre- 
vious to  its  being  prepared  for  dyeing,  as  a  much  richer  color 
is  thereby  obtained. 

The  adulterations  of  annotta  are  oxide  of  lead  and  ochre. 
These  may  be  detected  by  burning  a  small  quantity  of  it  in  a 
china  crucible;  if  pure,  no  residue  will  be  left;  but  if  oxide  of 
lead  be  the  adulterant,  by  keeping  the  crucible  at  a  red  heat,  a 
small  button  of  lead  will  be  obtained  ;  and  if  ochre  be  present, 
a  red  powder  will  be  left. 

The  liquid  sold  in  shops  under  the  name  of  Scott's  nankeen 
dye,  is  a  solution  of  annotta  and  potash  in  water. 

Annotta  is  often  used  for  coloring  butter  and  cheese. 


Nitric  acid 
Chromic  acid 


blue  as  it  does  with  annotta. 
A  yellow  shade. 
A  deep  orange  tint. 


352 


ALKANET  ROOT— AKCHIL. 


Alkanet  Root. 

This  is  the  root  of  a  plant  (Lithospermum  tinctorium)  which 
grows  in  the  Levant,  and  several  other  warm  countries.  It 
was  introduced  as  a  dye  a  few  years  ago,  but  with  little  success. 
The  coloring  matter  is  slightly  soluble  in  water,  but  is  rendered 
soluble  by  alkalies,  to  which  it  gives  a  blue  color,  also  by  oils 
and  fatty  substances,  which  it  colors  red.  It  has  the  following 
reactions: — 

Salts  of  lead  Blue  precipitates. 

Salts  of  tin  Crimson  precipitates. 

Salts  of  iron  Violet-colored  precipitates. 

Salts  of  alumina  Violet  precipitates. 

A  variety  of  shades  of  lavender,  lilac,  violet,  &c.  are  dyed  by 
this  coloring  matter,  but  caution  and  experience  are  necessary 
to  insure  success,  and  the  colors  obtained  are  easily  affected  by 
light,  which,  in  our  opinion,  is  the  greatest  barrier  to  its  use. 
Colors  formerly  were  generally  dyed  with  it  by  giving  the 
cloth  an  oil  or  soap  preparation,  the  soap  being  combined  with 
alumina  to  serve  as  the  base. 


Akchil. 

This  coloring  matter  is  prepared  from  lichens,  a  species  of 
sea-weed.  The  most/  esteemed  is  that  denominated  Lichen 
roccella.  The  best  sort  comes  from  the  Canary  and  Cape  de 
Verd  Islands;  but  it  is  also  found  abundantly  on  the  coasts  of 
Sweden,  Scotland,  Ireland,  and  Wales,  and  the  people  have 
from  time  immemorial  used  it  for  dyeing  cloths.  The  color- 
ing matters  prepared  from  these  lichens  have  been  long  known 
in  commerce  in  the  following  forms: — 

1st.  As  a  pasty  matter,  called  archil. 

2d.  A  mass  of  a  drier  character,  called  persis ;  and, 

3d.  As  a  red  powder,  called  cudbear. 

The  details  of  the  mode  of  preparing  archil  have  been  kept 
a  secret,  and  are  but  imperfectly  known  even  yet.  The  fol- 
lowing is  what  is  known:  The  lichens  are  first  ground  between 
two  stones  to  a  pulp,  with  the  addition  of  water,  and  afterwards 
put  into  a  wooden  trough,  having  a  tightly-fitted  cover;  upon 
the  moist  pulp  is  sprinkled  a  mixture  of  urine  and  ammonia, 
and  the  vessels  being  then  covered,  fermentation  soon  begins. 
The  whole  is  occasionally  stirred,  and  more  ammonia  and  urine 
are  added  from  time  to  time.    After  a  few  days,  the  color  be- 


ARCHIL. 


353 


gins  to  develop  itself,  but  about  six  weeks  are  required  to 
complete  the  operation.  The  whole  is  then  removed  from  the 
trough  and  placed  in  casks,  and  may  be  kept  for  years.  The 
keeping  is  considered  to  improve  the  intensity  of  the  color, 
which  should  be  of  a  deep  reddish-violet. 

Acids  change  the  color  to     .    Bright  red,  and 


Alkalies  to   A  blue. 

Sea-salt  gives  it       ....  A  crimson  tint. 

Sal  ammoniac   A  ruby-red  tint. 

Alum  throws  down     ...  A  brownish-red  precipitate. 

Salts  of  tin   Bed  precipitates. 

Salts  of  iron   Eed-brown  precipitates. 

Salts  of  copper   Cherry-brown  precipitates. 


There  are  no  mordants  required  for  dyeing  with  archil.  It 
is  not  used  for  cotton  dyeing,  but  extensively  for  silk  and 
woollens,  imparting  very  beautiful  tints,  which,  however,  are 
not  permanent.  It  is  often  used  as  a  bottom  color  for  reds 
which  are  to  be  dyed  by  safflower,  cochineal,  &c,  and  gives 
depth  and  a  beautiful  rich  tint  to  the  colors  so  dyed. 

The  coloring  principle  of  these  lichens,  and  especially  that 
producing  the  archil,  has  been  the  subject  of  extensive  inves- 
tigation with  some  of  the  first  chemists  both  in  this  and  other 
countries.  The  results  of  these  researches  are,  that  the  color- 
ing matter  of  these  lichens  depends  upon  the  oxidation  of  a 
colorless  base,  or  compound  existing  in  the  plant.  That  of 
archil  is  termed  orcine,  and  the  oxidized  color  is  known  as 
orceine.  Dr.  Stenhouse  has  given  very  simple  methods  of  ob- 
taining these  matters  from  the  lichens.  Could  this  color  be 
obtained  of  a  permanent  character,  and  fixed  upon  cotton,  its 
value  would  be  inestimable. 

The  process  of  Mr.  Stenhouse  consists  in  picking  and  wash- 
ing the  impurities  from  the  lichens,  which  are  afterwards  ground 
in  a  mill  to  a  liquid  paste.  By  successive  washings  of  this 
paste,  the  ligneous  bodies  remain  on  the  filter,  and  a  liquor  is 
obtained,  into  which  is  poured  some  bichloride  of  tin,  which 
precipitates  all  the  coloring  matter. 

The  latter  is  well  washed,  put  into  vats  with  a  certain  pro- 
portion of  ammonia,  and  frequently  stirred  for  a  few  days ;  the 
purple  coloration  gradually  appears,  and  the  maximum  is 
obtained  after  one  month  of  such  treatment.  It  is  sold  in 
paste,  or  in  the  dried  state. 

Archil  improves  by  being  kept  for  two  years;  at  the  third 
year  it  begins  to  deteriorate.  It  raises  considerably  the  shade 
of  indigo. 

In  1857,  Mr.  Marnas,  of  Lyons,  discovered  a  process  to  make 
26 


354 


ARCHIL. 


with  archil  a  color  remarkable  alike  for  its  beauty  and  fastness ; 
it  is  the  French  purple.  It  is  produced  in  the  following  man- 
ner : — 

Powdered  lichens  are  macerated  with  a  milk  of  lime,  in  order 
to  render  soluble  the  coloring  matter,  which  combines  with  the 
lime.  After  filtration,  hydrochloric  acid  is  added,  which  satu- 
rates the  lime,  and  causes  the  coloring  substance  to  separate 
in  a  gelatinous  state,  which  is  washed  and  dissolved  in  hot  am- 
monia. The  solution  is  very  slow,  as  it  requires  20  to  25 
days,  and  a  temperature  of  about  153°  Fahr.  The  ammoniacal 
liquid,  which  has  become  violet,  is  then  precipitated  by  chloride 
of  calcium  ;  a  purple  lake  is  thus  produced,  which  is  the  French 
purple. 

An  aluminous  lake  may  be  obtained  by  au  aluminous  rea- 
gent. .  This  last  preparation  is  considered  preferable  for  print- 
ing. 


355 


PROPOSED  NEW  VEGETABLE  DYES. 

There  are  occasionally  papers,  of  great  value  to  the  dyer, 
appearing  in  periodicals  and  the  reports  of  scientific  societies, 
that  are  not  seen  by  practical  men,  and  their  value  to  a  great 
extent  is  consequently  lost.  We  have  selected  a  few  in  proof 
of  this  statement,  and  trust  it  will  stimulate  to  a  more  active 
research  after  such  articles,  which  cannot  fail  to  be  productive 
of  good  results. 

SOORANJEE. 

This  substance  was  investigated  lately  by  Professor  Ander- 
son, from  whose  paper  we  give  the  following  account: — 

"  The  subject  of  these  experiments  was  imported  into  Glas- 
gow, some  time  since,  under  the  name  of  Sooranjee,  with  the 
intention  of  introducing  it  as  a  substitute  for  madder  in  the 
art  of  dyeing.  For  this  purpose  it  was,  on  its  arrival,  sub- 
mitted for  trial  to  some  of  the  most  experienced  and  skilful 
calico  printers  in  Glasgow,  all  of  whom  concurred  in  declaring 
it  not  to  be  a  dye  at  all,  and  to  be  totally  destitute  of  useful 
applications.  My  friend,  Professor  Balfour,  happening  to  hear 
of  this  circumstance,  was  so  good  as  to  obtain  for  me  a  quantity 
of  the  root,  which  has  enabled  me  to  submit  it  to  a  chemical 
investigation. 

"  Sooranjee  is  the  root  of  the  plant,  and  is  imported  cut  up 
into  pieces  from  one  to  four  inches  in  length,  and  varying  in 
diameter  from  a  half  down  to  nearly  an  eighth  of  an  inch.  On 
the  small  pieces  the  bark  is  thick,  and  forms  a  large  propor- 
tion of  the  whole  root,  but  on  the  larger  fragments  it  is  much 
thinner.  Its  external  color  is  pale  grayish-brown  ;  but  when 
broken  across,  it  presents  colors  varying  from  fine  yellow  to 
brownish-red,  and  confined  principally  to  the  bark.  The  wood 
itself  has  only  a  slight  yellowish  shade,  deepest  in  the  centre, 
and  scarcely  apparent  close  to  the  bark ;  but  it  is  colored  dark- 
red  by  alkalies,  indicating  the  presence  of  a  certain  quantity 
of  coloring  matter  in  it.  The  bark  is  readily  detached  and 
its  inner  surface,  as  well  as  that  of  the  wood,  has  a  peculiar 
silvery  appearance,  most  apparent  on  the  large  pieces  and  al- 
most entirely  absent  in  the  smaller.  Boiled  with  water,  it  gives 
a  wine-yellow  decoction,  and  with  alcohol  a  deep-red  tincture. 


356 


SOORANJEE. 


"Solution  of  morindine  gives  with  subacetate  of  lead  a  pre- 
cipitate, depositing  itself  in  crimson  flocks,  which  is  extremely 
unstable,  and  cannot  be  washed  without  losing  coloring  matter. 
With  solutions  of  baryta,  strontia,  and  lime,  it  gives  bulky-red 
precipitates  sparingly  soluble  in  water.  Perchloride  of  iron 
produces  a  dark-brown  color,  but  no  precipitate.  When  its 
ammoniacal  solution  is  added  to  that  of  alum,  the  alumina  pre- 
cipitated carries  down  with  it  the  morindine  as  a  reddish-lake, 
and  when  added  to  perchloride  of  iron,  a  brown  precipitate  is 
thrown  down,  which  cannot  be  distinguished  from  pure  per- 
oxide of  iron,  but  which  contains  morindine,  as  the  supernatant 
fluid  is  colorless. 

"The  formula  thus  ascertained  brings  out  an  interesting  re- 
lation between  morindine  and  the  coloring  matters  of  madder, 
and  more  especially  that  one  which  is  obtained  by  the  sublima- 
tion of  madder  purple.  From  his  analysis  of  this  substance, 
Schiel*  deduces  the  formula  C7  H4  04.  As  this,  however,  is 
no  more  than  the  simplest  expression  of  the  analytical  results, 
and  as  all  the  other  madder-coloring  matters  examined  con- 
tained 28  equivs.  of  carbon,  we  are  justified  in  supposing  its 
real  constitution  to  be  represented  by  quadruple  of  that  for- 
mula, or  C28  Hj6  016,  which  differs  from  that  of  morindine  by 
a  single  equivalent  of  water  only.  The  unsublimed  madder- 
purple  is  also  connected,  though  more  remotely,  with  morindine, 
and  differs  only  by  containing  5  equivs.  of  hydrogen  less,  its 
formula  according  to  Schiel  being  C28  H10  015. 

"This  similarity,  however,  does  not  extend  itself  to  their 
properties  as  dyes,  in  which  respect  they  differ  in  a  very  re- 
markable manner.  I  have  already  mentioned  that  the  calico- 
printers  had  entirely  failed  in  producing  a  color  by  means  of 
sooranjee,  and  this  I  have  fully  confirmed  as  regards  the  com- 
mon mordants.  I  digested  morindine,  for  a  long  time,  in  a 
gradually  increasing  heat,  with  small  pieces  of  cloth  mordanted 
with  alumina  and  iron;  but  nothing  attached  itself;  and  the 
mordants,  after  boiling  for  a  minute  or  two  with  soap,  were 
found  to  be  unchanged.  Even  with  the  root  itself  alum  mor- 
dant only  acquired  a  slight  reddish-gray  shade,  and  iron  became 
scarcely  appreciably  darker  in  color.  The  case  was  different, 
however,  when  cloth  mordanted  for  Turkey  red  was  employed. 
I  obtained  from  Glasgow  pieces  of  calico  prepared  for  Turkey- 
red  both  by  the  old  and  new  processes;  and  I  found  that  both 
acquired  with  morindine,  in  the  course  of  a  couple  of  hours, 
or  even  less,  a  dark  brownish-red  color,  devoid  of  beauty,  but 
perfectly  fixed.    These  observations  agree  with  the  account 


*  Chemical  Gazette,  vol.  v.  p.  77. 


SOORANJEE. 


357 


given  by  Mr.  Hunter,  of  the  method  of  dyeing  with  the  M. 
citrifolia  employed  by  the  Hindoos.  The  cloth  is  first  soaked 
in  an  imperfect  soap,  made  by  mixing  the  oil  of  the  Sesamum 
orientate  with  soda-lye.  After  rinsing  and  drying,  it  is  treated 
with  an  infusion  of  myrobalans  (the  astringent  fruit  of  the 
Terminalia  chebula),  and  exposed  for  four  or  five  days  in  the  sun. 
Ifr  is  then  steeped  in  solution  of  alum,  squeezed,  and  again 
exposed  for  four  or  five  days.  On  the  other  hand,  the  powdered 
roots  of  the  Morinda  are  well  rubbed  with  oil  of  sesamum,  and 
mixed  with  the  flowers  of  the  Lythrum  fruticosum  (Roxburgh), 
or  a  corresponding  quantity  of  purwas  (the  nut-gall  of  a  species 
of  Mimosa).  The  whole  is  introduced  along  with  the  cotton 
into  a  large  quantity  of  water,  and  kept  over  a  gentle  fire  for 
three  hours,  when  the  temperature  is  brought  to  the  boiling 
point.  The  red  color  so  obtained  is,  according  to  Mr.  Hunter, 
more  prized  for  its  durability  than  its  beauty.  This  is  simply 
a  rude  process  of  Turkey-red  dyeing.  He  also  mentions,  that 
by  means  of  an  iron  mordant,  a  lasting  purple  or  chocolate  is 
obtained;  but,  in  this  case,  the  color  is  probably  affected  by 
the  tannin  of  the  astringent  matters  employed  in  the  process. 

Ct  Morindine  is  a  true  coloring  matter,  and  is  capable  of  at- 
taching itself  to  common  mordants.  It  gives,  with  alumina,  a 
deep  rose-red,  and  with  iron,  violet  and  black;  but  the  colors 
are  not  very  stable,  and  it  has  a  strong  tendency  to  attach  itself 
to  the  unmordanted  parts  of  the  cloth,  and  to  degrade  the  white. 
Morindine,  after  treatment  with  sulphuric  acid,  is  capable  of 
attaching  itself  to  ordinary  mordants. 

"  The  discovery  of  a  peculiar  coloring  matter,  capable  of  fix- 
ing itself  exclusively  on  Turkey-red  mordant,  is  of  interest,  as 
establishing  the  existence  of  a  peculiar  class  of  dyes  hitherto 
totally  unsuspected — a  class  which  maybe  extensive,  and  may 
yield  important  substances.  It  may  serve  also,  in  some  respects 
to  clear  up  the  rationale  of  the  process  of  Turkey-red  dyeing, 
which  has  long  been  a  sort  of  opprobrium  on  chemistry. 
Although  that  process  has  been  practised  for  a  century  in 
Europe,  and  has  undergone  a  variety  of  improvements,  no  clear 
explanation  of  it  was  for  a  long  time  given ;  but  it  was  sup- 
posed that  by  the  action  of  the  dung,  of  which  large  quantities 
are  employed,  the  cloth  underwent  a  species  of  animalization, 
as  it  was  called,  bj  which  it  acquired  the  property  of  receiving 
a  finer  and  more  brilliant  color  than  could  be  attached  to  it  by 
purely  mineral  mordants.  Eecent  experiments  have,  however, 
shown  that  the  oil,  which  is  largely  employed  in  the  process, 
undergoes  decomposition  by  long  exposure  to  the  air  in  con- 
tact with  decomposing  animal  matter,  and  is  converted  into  a 
sort  of  resinous  matter,  which  constitutes  the  real  mordant  for 


358 


CARAJURU,  OR  CHICA. 


Turkey-red.  This  has  been  pretty  clearly  made  out  by  the 
experiments  of  Weissgerber  *  He  found  that  when  cloth  had 
been  treated  with  oil,  so  as  to  give  when  dyed  a  fine  rose-red 
color,  he  could,  by  digestion  with  acetone,  extract  from  it  the 
altered  oil ;  and,  as  it  was  removed,  the  cloth  gradually  lost 
the  power  of  attracting  the  coloring  matter  of  madder,  until, 
when  it  was  entirely  separated,  the  cloth  passed  through  tbe 
dye  without  acquiring  any  color.  On  the  other  hand,  he  found 
that,  by  applying  the  substance  extracted  by  acetone  in  suffi- 
cient quantity  to  cloth,  he  could  obtain  the  richest  and  deepest 
colors  with  madder,  without  the  addition  of  any  other  sub- 
stance whatsoever.  These  observations  receive  additional  con- 
firmation from  the  experiments  detailed  in  the  present  paper, 
as  it  must  be  sufficiently  obvious  that  the  dark-red  color 
obtained  on  Turkey-red  mordant,  with  morindine,  must  be 
entirely  irrespective  of  the  alumina,  on  which  that  substance  is 
incapable  of  fixing. 

"  I  fully  agree  with  the  opinion  expressed  by  Persoz,  that 
the  use  of  alum  mordant,  which  is  at  present  always  employed 
in  Turkey-red  dyeing,  will  be  entirely  abandoned  as  soon  as 
calico  printers  have  learned  the  method  of  modifying  at  will 
the  oil  which  they  employ,  so  as  to  bring  it  at  once  into  the 
state  in  which  it  acts  as  a  mordant.  Some  steps  have  been 
made  in  this  direction  by  making  use  of  some  chemical  agents, 
as  nitric  acid  and  chloride  of  lime,  for  the  purpose  of  acting  on 
the  oil;  but  the  improvements  which  have  been  effected  stop 
far  short  of  what  I  believe  will  eventually  be  effected  when  the 
system  of  pure  empiricism,  which  has  been  all  along  employed 
in  this  particular  process  of  dyeing,  is  abandoned,  and  the  sub- 
ject submitted  to  really  scientific  investigation.  It  is  under- 
stood that  M.  Chevreul  has  entered  upon  the  inquiry,  and  in 
his  hands  there  is  little  doubt  but  that  it  will  meet  with  a 
satisfactory  solution." — From  the  Transactions  of  the  Royal 
Society  of  Edinburgh. 

Carajuru,  or  Chica 

Is  a  vegetable  substance  known  by  these  names,  and  is 
obtained  from  America,  where  it  is  used  by  the  natives  as  a 
dye.  The  following  short  extracts  from  a  paper  by  J.  J.  Virey , 
will  show  its  character  and  properties: — 

u  M.  de  Humboldt  has  described  in  the  Annales  de  Ghimie  et 
de  Physique  (vol.  xxvii.  p.  315),  under  the  name  of  Chica,  a 
vegetable  product  of  a  brick-red  color,  obtained  by  macerating 

*  Persoz,  sur  Tlmpression  des  Tissus,  vol.  iii.  p.  176. 


WONGSHY. 


359 


in  water  the  leaves  of  Bignonia  chica,  a  shrub  of  the  family  of 
the  Bignoniacece  from  equinoctial  America. 

"  As  we  have  obtained  from  Para  in  Brazil,  under  the  de- 
nomination Crajuru,  or  Carajuru,  a  substance  not  only  analo- 
gous in  its  physical  and  chemical  characters  to  the  Chica,  but 
of  a  red-brown  violet  tint  much  more  beautiful  and  rich,  and 
like  vermilion,  while  the  other  appeared  duller  and  much 
inferior,  it  may  be  useful  to  give  fresh  details  about  this  pro- 
duct, which  has  been  imported  to  be  tried  in  dyeing. 

"The  Crajuru,  or  Carajuru  (Carucuru,  according  to  others), 
is  a  kind  of  powder,  or  fecula,  in  pieces  somewhat  light,  inodor- 
ous, insipid  or  slightly  bitter,  not  soluble  in  water,  but  soluble 
in  alcohol,  ether,  and  the  oils  and  fats,  without  being  com- 
pletely resinous,  burning  with  a  flame,  but  leaving  a  quantity 
of  gray  cinders.  It  is  wholly  dissolved  by  alkalies,  and  acids 
precipitate  it  without  greatly  altering  its  color,  if  they  are  not 
concentrated. 

"The  Crajuru  now  brought  into  Europe  must  furnish  a 
rather  strong  and  beautiful  dye,  the  brilliancy  of  which  appears 
quite  superior  to  that  of  Orleans."* 

WONGSHY 

Ts  another  vegetable  substance.  An  investigation  of  its 
properties  was  made  by  W.  Stein,  from  whose  paper  we  ex- 
tract the  following  account: — 

u  Towards  the  end  of  last  year,  a  new  material  for  dyeing 
yellow,  called  wongsky,  was  exported  on  experiment  from 
Batavfa  to  Hamburg,  for  a  sample  of  which  I  am  indebted  to 
the  kindness  of  M.  Vollsack,  merchant.  Whether  it  has 
hitherto  been  applied  as  a  dyeing  material,  and  with  what 
results,  could  not  be  ascertained.  The  following  notice,  there- 
fore, will  probably  not  be  without  interest : — 

"The  new  dyeing  material  consists  of  the  seed-vessels  of  a 
plant,  which,  according  to  the  information  from  M.  Reichen- 
bach,  belongs  to  the  family  of  the  Gentianeaa.  The  form  of 
the  unilocular  capsules  is  longish-ovate,  drawn  out  to  a  point 
next  the  end  of  the  peduncle,  and  crowned  upon  the  opposite 

*  "  The  drink  called  chica,  which  is  so  much  used  among  the  people  of 
South  America,  must  not  be  confounded  with  the  subject  of  the  present 
notice.  This  drink,  in  fact,  is  prepared  with  pods  of  algaroba,  (Mimosa 
algaroba),  which  are  nearly  as  sweet  as  the  carouba  of  the  Ceratonia  Siliqua, 
and  with  the  bitter  stalks  of  the  Schinus  molle.  It  said  that  old  women  are 
employed  to  chew  these  Algarobce  and  the  Schinus,  and  then  to  spit  them 
into  a  vessel ;  water  is  added ;  the  whole  soon  ferments,  and  affords  a  kind 
of  intoxicating  beer." 


360 


WONGSHY. 


and  more  obtuse  one  with  the  dried  six-lobed  calyx.  They 
vary  in  size;  but  on  an  average  their  length  is  1.5  to  2  inches, 
and  the  diameter  at  the  thickest  part  0.5 ;  the  color  is  not  uni- 
formly reddish-yellow,  but  at  some  places  darker,  at  others 
lighter.  The  surface  is  more  or  less  irregularly  waved  with 
six  to  eight  longitudinal  ribs.  The  odor  resembles  saffron,  and 
subsequently  honey.  The  shell  is  pretty  hard  and  brittle,  but 
becomes  quickly  mucilaginous  when  chewed,  imparting  a  yel- 
low color  to  the  saliva,  with  a  slightly  bitter  taste;  it  swells 
up  considerably  in  water.  Inside  the  capsules  there  are  a 
number  of  dark  reddish-yellow  seeds  (in  one  specimen  I 
counted  108);  they  are  not  attached  to  the  sides,  but  are  im- 
bedded in  a  hardened  pulp,  and  so  connected  one  with  the 
other.  These  seeds  are  tolerably  hard,  soften  but  slowly  when 
chewed,  have  no  particular  taste,  but  after  some  time  produce 
at  the  point  of  the  tongue  a  slight  but  peculiar  sourish-sweet 
pungency,  resembling  the  action  of  Paraguay  rue.  The  pulp, 
on  the  other  hand,  cementing  them  together,  has  a  strong  bit- 
ter taste,  which  is  particularly  perceptible  at  the  back  part  of 
the  palate. 

"The  wongshy,  especially  when  pounded,  readily  gives  up 
to  water,  both  at  the  usual  temperature  as  well  as  on  boiling, 
a  coloring  principle,  which  possesses  such  an  enormous  divisi- 
bility that  two  parts  of  the  pounded  capsules  furnish  128  parts 
of  a  liquid,  which  placed  in  a  cylindrical  vessel  of  white  glass 
with  a  diameter  of  three  inches  still  appears  of  a  bright  wine- 
yellow  color.  The  concentrated  extract  is  very  mucilaginous, 
and  has  a  fiery-red  color,  which,  on  large  dilution,  passes  into 
a  golden-yellow,  the  red  disappearing.  % 

"  Protochloride  of  tin  produces  no  change  at  the  ordinary 
temperature,  or  after  a  long  time;  on  boiling,  a  dark  orange- 
colored  precipitate  results. 

"Acetate  of  lead  produces  no  change. 

"  Basic  acetate  of  lead  causes  a  turbidness  at  the  ordinary 
temperature,  and  an  orange-colored  precipitate  on  boiling. 

"Protosulphate  of  iron  changes  the  color  into  a  dark  brown- 
ish-yellow, without,  however,  a  precipitate  resulting  either  in 
the  cold  or  on  ebullition. 

"Alum,  acetate  of  alumina,  and  acetate  of  zinc,  produce 
yellow  precipitates  only  on  boiling. 

"Barytic  water  causes  a  yellow  precipitate  at  the  ordinary 
temperature,  which  on  boiling  acquires  a  reddish  tint. 

"Lime-water  gave  a  pure  yellow  precipitate;  solutions  of 
gypsum  and  chloride  of  calcium  are  not  precipitated  by  it  even 
on  boiling;  well  water,  with  a  considerable  amount  of  carbon- 
ate of  lime,  does  not  precipitate  the  coloring  principle  even 


WONGSHY. 


361 


with  the  assistance  of  heat;  it  is,  consequently,  not  able  to 
decompose  the  combinations  of  lime  with  acids. 

"To  ascertain  the  value  of  the  wongshy  coloring  matter  for 
the  purposes  of  dyeing,  1  part  of  the  pounded  capsules  was 
digested  for  twelve  hours  with  20  parts  of  lukewarm  water, 
being  frequently  stirred,  and  the  liquid  then  strained.  The 
coloring  matter  is  most  quickly  extracted  in  this  manner  with- 
out its  becoming  gelatinous  from  the  formation  of  paste,  as 
would  happen  were  the  liquid  boiled.  Properly  prepared 
samples  of  woollen  cloth,  some  without  any  mordant,  others 
mordanted  with  alum,  protochloride  of  tin,  acetate  of  alumina, 
and  basic  acetate  of  lead,  were  dyed  with  this  extract  at  a 
temperature  of  about  104°  Fah. ;  the  color  does  not  turn  out 
so  pure  at  a  higher  temperature.  The  unmordanted  cloth  was 
dyed  a  beautiful  and  uniform  orange  color  by  one  immersion  ; 
of  the  mordanted  samples,  those  with  alum  and  acetate  of 
alumina  were  better  than  those  with  protochloride  of  tin  ;  the 
least  satisfactory  was  that  in  which  basic  acetate  of  lead  had 
been  used  as  mordant.  The  tone  of  the  color  was  not  altered 
by  the  first  three  mordants,  but  it  was  less  intense,  and  the 
stuffs  were  not  uniformly  penetrated  by  the  coloring  matter. 
However,  the  samples  with  alum  mordant  gave  perfectly  satis- 
factory results  after  a  second  immersion.  The  coloring  matter 
likewise  combines  readily  and  uniformly  with  silk,  communi- 
cating to  it  a  very  glowing  golden  color,  so  that  in  this  case  I 
also  prefer  not  having  recourse  to  mordants.  Cotton,  as  was 
to  be  expected,  can  only  be  dyed  with  the  assistance  of  mor- 
dants, and  the  best  results  appeared  to  be  obtained  with  tin 
mordants  ;  the  color  was  orange,  of  a  very  agreeable  tint. 

"The  color,  both  upon  wool,  silk,  and  cotton,  resists  soap 
perfectly ;  but  alkalies  give  it  a  yellow,  acids  and  tin  salt,  a  red 
tint.  By  this  behavior  it  differs  from  the  color  of  annotta,  with 
which,  as  will  subsequently  be  seen,  it  possesses  in  other 
respects  great  resemblance,  a  resemblance  which  unfortunately 
exists  as  regards  the  action  of  light.  When  exposed  to  light, 
the  color  very  soon  fades  upon  cotton,  less  quickly  upon  wool; 
and  in  this  case  it  is  more  permanent  upon  the  unmordanted 
samples.  It  resists  the  light  longest  upon  silk;  and,  in  this 
respect,  when  compared  with  the  other  known  yellow  colors, 
may  be  reckoned  among  the  best. 

UI  obtained  a  beautiful  yellow,  with  a  faint  tint  of  red,  by 
mordanting  the  woollen  cloth  with  lime  water,  and  immersion 
in  the  boiling  vat ;  it  resists  the  soap  perfectly,  and  the  action 
of  light  much  better  than  the  orange.  It  is  altered  in  a  similar 
manner  to  the  orange  by  alkalies,  acids,  and  tin  salt,  only  less. 
Several  very  beautiful  shades  of  yellow  may  be  obtained  by 


862 


WOXGSHY. 


adding  pearlash  or  caustic  potash  to  the  dye,  and  immersing 
the  unmordanted  fabric  at  the  ordinary  temperature.  The 
union  of  the  color  with  the  fibre  takes  place  very  quickly  and 
very  uniformly.  By  the  addition  of  1  part  pearlash  to  30 
parts  dye  liquor,  a  yellow  was  obtained  with  a  remarkable 
glow  from  a  slight  admixture  of  red.  By  the  addition  of  twice 
the  quantity  of  pearlash,  a  lively  yellow,  with  a  faint  tint  of 
green,  was  obtained.  A  still  larger  amount  of  pearlash  cannot 
be  used,  as  it  renders  the  color  dull  and  impure.  With  caustic 
potash,  instead  of  pearlash,  I  obtained,  in  the  first  place,  a  pure 
brilliant  yellow,  with  less  red  than  with  the  pearlash ;  in  the 
latter  case,  a  beautiful  Canary-yellow  with  a  shade  of  green. 
Ammonia  acts  in  the  same  manner,  but  the  color,  under  all 
circumstances,  contains  more  red.  The  color  also  appears  of  a 
somewhat  different  shade  when  the  fabrics  are  first  immersed 
in  the  dye  liquor,  and  then,  after  being  washed,  placed  in  an 
alkaline  bath. 

"In  the  case  of  silk  and  cotton,  the  effect  of  alkalies  is  similar, 
but  less  apparent,  because  the  silk  and  cotton  fibres  imbibe  less 
of  the  coloring  substance  than  those  of  wool. 

"That  this  color  resists  the  soap  is  self-evident,  but  it  also 
suffers  less  from  the  action  of  light  than  the  orange  ;  and  when 
fabrics  so  dyed  are  passed  through  a  vinegar  or  muriatic  acid 
bath,  a  brilliant  aurora  color  is  obtained.  This  interesting 
behavior,  which  the  wongshy  coloring  matter  has  in  common 
with  that  of  annotta,  is  explained  by  the  chemical  character  of 
the  former,  which  is  a  weak  acid ;  it  combines  with  the  alkalies 
and  with  the  alkaline  earths,  as  evident  by  the  precipitation 
with  baryta  and  lime-water.  Its  combinations  with  the  former 
possess  a  pure  yellow  color,  and  are  decomposed  by  stronger 
acids,  when  the  liberated  coloring  matter  separates  of  a  brilliant 
vermilion  color.  But  the  coloring  matter  thus  separated  is  no 
longer  the  same  as  that  which  was  originally  contained  in  the 
aqueous  solution,  for  it  is  now  perfectly  insoluble  in  water,  and 
is  only  dissolved  in  small  quantity,  and  of  a  golden-yellow 
color,  by  absolute  alcohol,  ether,  and  spirit  of  0.863  spec.  grav. 
In  the  moist  state,  it  has  a  vermilion  color;  when  dry  and  in 
the  purest  state  it  is  brown-red,  like  Eatanhia  extract,  and  is 
easily  reduced  to  powder ;  but  if  it  still  contains  sugar  and  fat, 
it  has  a  beautiful  yellowish-red  color,  in  thick  layers,  whilst  in 
thin  layers  it  is  yellow  and  transparent,  and  becomes  moist  in 
the  air.  On  heating  the  pure  substance  upon  platinum,  at  first, 
yellow  vapor  is  given  off,  and  at  some  spots  the  color  becomes 
pure  yellow;  it  subsequently  turns  black,  fuses,  and  chars. 
The  residual  cinder  is  difficult  to  burn  ;  the  yellow  vapors  con- 
dense, when  the  experiment  is  made  in  a  glass  tube,  into  yellow 


ALOES.  /  • 

oily  drops.  Concentrated  sulphuric  acid  renders  it  scarcely 
perceptibly  blue,  and  the  acid  acquires  the  same  color,  which 
quickly  passes  into  violet  and  brownish-red,  whilst  the  coloring 
matter  slowly  dissolves.  Water  separates  from  this  solution  a 
dirty  yellowish-gray  flocculent  substance. 

"The  reaction  of  the  wongshy  coloring  matter  which  has 
just  been  mentioned,  has  no  resemblance  with  the  reaction  of 
sulphuric  acid  upon  annotta,  for  the  liquid  never  acquires  a 
pure  blue  color,  as  is  the  case  with  annotta,  but  is  violet  from 
the  first,  and  only  for  a  minute. 

"It  dissolves  readily  in  caustic  ammonia  and  caustic  soda, 
with  a  golden  yellow  color." 


Aloes. 

Dr.  Bancroft,  in  his  work  on  the  Philosophy  of  Permanent 
Colors,  recommended  this  substance  as  a  dyeing  agent.  He 
proposed  to  digest  it  in  nitric  acid,  by  which  means  he  obtained 
aloetic  acid,  a  substance  capable  of  being  used  as  a  dye.  This 
matter  has  been  the  subject  of  extensive  investigation  by  many 
chemists,  and  has  been  occasionally  more  or  less  used  as  a  dye- 
ing agent.  A  patent,  however,  has  recently  been  taken  out 
for  certain  applications  of  aloes  to  dyeing.  The  following  is 
the  proposed  method  of  preparation: — 

"The  mode  of  preparing  the  coloring  matter  from  aloes  is 
as  follows :  Into  a  boiler  or  vessel,  capable  of  holding  about 
100  gallons,  the  patentee  puts  10  gallons  of  water,  and  132  lbs. 
of  aloes,  and  heats  the  same  until  the  aloes  is  dissolved;  he 
then  adds  80  lbs.  of  nitric  or  nitrous  acid,  in  small  portions  at 
a  time,  to  prevent  the  disengagement  of  such  a  quantity  of 
nitrous  gas  as  would  throw  part  of  the  contents  out  of  the 
boiler.  When  the  whole  of  the  acid  has  been  introduced,  and 
the  disengagement  of  gas  has  ceased,  10  lbs.  of  liquid  caustic 
soda,  or  potash  of  commerce,  of  about  80°  are  added,  to  neutral- 
ize any  undecomposed  acid  remaining  in  the  mixture,  and  to 
facilitate  the  use  of  the  mixture  in  dyeing  and  printing.  If 
the  coloring  matter  is  required  to  be  in  a  dry  state,  the  mixture 
may  be  incorporated  with  100  lbs.  of  China  clay,  and  dried  in 
stoves,  or  by  means  of  a  current  of  air.  In  preparing  the 
coloring  matter  from  extract  of  logwood,  the  materials  are  used 
in  the  manner  and  proportions  above  described;  the  only  dif- 
ference being,  that  the  extract  of  logwood  is  substituted  for  the 
aloes. 

"The  coloring  matter  is  used  in  dyeing  by  dissolving  a  suffi- 
cient quantity  in  water,  according  to  the  shade  required,  and 


364 


PITTACAL — BARBARY  ROOT. 


adding  as  much  hydrochloric  acid  or  tartar  of  commerce  as  will 
neutralize  the  alkali  contained  in  the  mixture,  and  leave  the 
dye-bath  slightly  acidulated.  The  article  to  be  dyed  is  intro- 
duced into  the  bath,  which  is  kept  boiling  until  the  desired 
shade  is  obtained. 

"When  the  coloring  matter  is  to  be  used  in  printing,  a  suffi- 
cient quantity  is  to  be  dissolved  in  water,  according  to  the  shade 
required  to  be  produced;  this  solution  is  to  be  thickened  with 
gum,  or  other  common  thickening  agent;  and  hydrochloric 
acid,  or  tartar  of  commerce,  or  any  other  suitable  supersalt  is 
to  be  added  thereto,  for  the  purpose  before  mentioned.  After 
the  fabrics  have  been  printed  with  the  coloring  matter,  they 
should  be  subjected  to  the  ordinary  process  of  steaming,  to  fix 
the  color."— Sealed,  Jan.  27,  1847. 

Pittacal. 

This  substance  is  obtained  from  beech  tar.  It  is  dry  and 
hard,  very  brittle,  and  resembles  indigo  in  appearance.  It  has 
no  taste  or  smell,  and  does  not  dissolve  in  water.  Sulphuric 
acid  dissolves  it,  producing  a  violet-colored  solution.  Muriatic 
acid  gives  a  red-purple  solution,  from  which  alkalies  precipi- 
tate the  pittacal.  Acetate  of  lead,  salts  of  tin,  sulphate  of  cop- 
per, acetate  of  alumina,  all  give  deep-blue  precipitates,  not 
readily  changed.  This  color  is  easily  fixed  upon  cotton  by  tin 
and  alumina.*    It  is  sometimes  used  for  blueing  linens. 

Barbary  Eoot. 

The  plant  from  which  this  is  obtained  grows  in  almost  every 
part  of  the  world;  great  quantities  of  it  are  obtained  from  India, 
where  it  grows  in  great  abundance  and  perfection.  The  color- 
ing matter  is  found  in  the  whole  of  the  root.  In  the  stem  it  is 
found  around  the  pith  and  near  the  bark.  This  coloring  sub- 
stance is  much  used  in  dyeing  or  staining  leather;  but  it  is  not 
much  used  in  the  dyeing  of  cotton.  Mr.  Edward  Solly  has 
made  some  investigations  of  this  root.  See  Journal  of  the 
Royal  Asiatic  Society, 

*  Records  of  General  Science. 


365 


ANIMAL  MATTERS 

USED  IN  DYEING. 


The  coloring  substances  of  this  chapter,  belonging  to  the 
animal  kingdom,  are  but  few  in  number,  and  are  used  especi- 
ally for  dyeing  animal  fibres.  They  are  employed  to  a  certain 
extent  for  calico  printing. 

Cochineal. 

This  is  a  small  insect  called  the  coccus  cacti,  and  is  much 
sought  after  for  its  tinctorial  qualities.  It  furnishes  the  finest 
known  shades  of  crimson,  red,  purple,  scarlet,  &c,  for  woollens 
and  silk.  The  insects  are  reared  in  great  abundance  in  Mexi- 
co. They  feed  upon  a  cactus  plant,  which  the  natives  cultivate 
around  their  dwellings  for  that  purpose.  The  insects  attach 
themselves  to  the  leaves  of  the  plant,  and  increase  rapidly  in 
number.  The  females  live  about  two  months,  and  the  males 
only  about  one  month.  The  season  of  rearing  and  gathering 
lasts  about  seven  months,;  during  this  period  the  insects  are 
gathered  three  times.  After  each  gathering,  some  of  the  branches 
and  leaves  containing  females  and  their  young  are  preserved 
under  shelter,  and  on  the  return  of  the  proper  season  they  are 
distributed  over  the  plantation.  A  few  females  are  put  into  a 
small  nest  made  of  some  downy  substance,  and  the  young  in- 
sects quickly  spread  themselves  out  upon  the  leaves,  to  which 
they  attach  themselves.  They  are  gathered  by  brushing  them 
off  the  leaves  with  the  feather  end  of  a  quill  into  boiling  hot 
water,  in  which  they  are  kept  a  few  seconds.  This  not  only 
kills  them  instantly,  but  causes  them  to  swell  to  twice  their 
natural  size.  When  taken  out  the  hot  water,  they  are  spread 
out  and  dried,  and  then  packed  for  the  market.  Some  culti- 
vators instead  of  hot  water  use  steam,  and  others  again  place 
them  in  an  oven  or  upon  a  hot  plate.  The  difference  in  the 
appearance  of  the  cochineal  is  caused  by  these  different  modes 
of  killing  the  insects  and  heating  them.  They  shrivel  in  dry- 
ing, and  assume  the  appearance  of  irregular  formed  grains, 
fluted  and  concave.    The  best  sorts  seem  as  if  dusted  with  a 


366 


COCHINEAL. 


4.  Saline  matters,  as 


white  powder,  and  are  of  a  slate-gray  color ;  but  these  appear- 
ances are  often  imparted  by  means  of  powdered  talc,  to  deceive 
the  purchaser. 

There  are  several  kinds  of  cochineal  in  commerce.  The  finest 
is  known  by  the  name  of  mistic,  from  the  name  of  the  place  in 
which  the  insects  are  reared,  La  Mistica,  in  the  province  of 
Honduras.  Another  is  called  wild,  because  they  are  collected 
from  plants  growing  in  a  state  of  nature;  but  this  variety  is 
inferior  to  the  former.  The  third  is  a  mixture  of  these  two,  or 
rather  the  debris  or  fragments,  and  varies  in  quality  according 
to  the  proportion  of  the  mixture. 

Cochineal  has  been  the  subject  of  several  chemical  investi- 
gations, the  results  of  which  are  not  very  satisfactory.  The 
following  are  instances  of  these.    The  cochineal  contains: — 

1.  Carmine,  which  may  be  termed  the  coloring  matter. 

2.  A  peculiar  animal  matter. 

A  fatty  matter,  composed  (  gi^e^and 

(  Volatile  fatty  acids. 
Phosphate  of  lime. 
Carbonate  of  lime. 
Chloride  of  potassium. 
Phosphate  of  potash. 
Combination  of  potash  with 
organic  acids. 

Mr.  John  gives  the  following  as  the  result  of  his  analysis  : — 

Ked-coloring  matter  50.0 

Gelatin  10.5 

Wax  10.0 

Debris  of  skin,  &c  14.0 

Gummy  matter  13.0 

Phosphate  of  lime,  of  potash,  and  iron,  and  chloride  ) 
of  potassium  f 

Carmine,  or  the  coloring  matter  of  cochineal,  may  be  obtained 
by  macerating  finely  ground  cochineal  with  ether,  which  dis- 
solves out  the  fatty  matter,  and  then  dissolving  the  carmine  by 
the  application  of  hot  alcohol,  and  leaving  the  solution  to  cool; 
by  evaporating,  the  carmine  is  deposited  as  a  beautiful  red 
crystalline  substance,  which  dissolves  freely  in  water.  It  is 
affected  by  the  following  reagents  as  under: — 

Tannin  «  Gives  no  precipitate. 

Most  acids  Change  its  color  from  a  bright 

to  a  yellowish-red. 
Boracic  acid  Does  not  change  the  color,  but 

rather  reddens  it  more. 


TESTS  FOR  COCHINEAL. 


367 


Potash,  soda  and  ammonia  .  Change  it  to  a  crimson-violet. 
Baryta  and  strontia  .    .    .  Produce  the  same  effect. 


Lime  Gives  a  crimson- violet  precipi- 
tate. 

Alumina  Combines  with  it  and  precipi- 
tates it  as  a  beautiful  red ; 
but  if  boiled,  it  passes  to  violet- 
red. 


A  little  potash,  soda,  or  am- 
monia added  prevents  this 
change,  and  preserves  the 
stability  of  the  red. 
Protoxides  of  tin  .    .    .    .  Change  it  to  crimson-violet. 


Peroxide  of  tin     ....  Changes  it  to  yellowish-red. 
Salts  of  iron  Turn  it  brown ;   no  precipi- 
tate. 

Salts  of  lead  Change  it  to  violet;  no  precipi- 
tate. 

Salts  of  copper  Change  it  to  violet;  no  precipi- 
tate. 

Nitrate  of  mercury    .    .    .  Gives  a  scarlet-red  precipitate. 
Nitrate  of  silver    ....  Has  no  action  upon  it. 
Chlorine  Turns  it  yellow. 


"  As  may  be  supposed,  the  result  of  all  these  contrary  opinions 
is,  that  it  is  perfectly  impossible  to  judge  of  the  goodness  of  a 
cochineal  by  its  physical  character.  In  order  to  ascertain  its 
value,  we  must  have  recourse  to  comparative  experiments.  We 
are  indebted  to  MM.  Eobiquet  and  Anthon  for  two  methods  of 
determining  the  quality  of  cochineals,  according  to  the  quan- 
tity of  carmine  they  contain.  The  process  of  M.  Eobiquet 
consists  in  decolorizing  equal  volumes  of  decoction  of  different 
cochineals  by  chlorine.  By  using  a  graduated  tube,  the  quality 
of  the  cochineal  is  judged  of  by  the  quantity  of  chlorine  em- 
ployed for  decolorizing  the  decoction.  The  process  of  M.  An- 
thon is  founded  on  the  property  which  the  hydrate  of  alumina 
possesses  of  precipitating  the  carmine  from  the  decoction  so  as 
to  decolorize  it  entirely.  The  first  process,  which  is  very  good 
in  the  hands  of  a  skilful  chemist,  does  not  appear  to  us  to  be 
a  convenient  method  for  the  consumer:  in  the  first  place,  it  is 
difficult  to  procure  perfectly  identical  solutions;  in  the  next 
place,  it  is  impossible  to  keep  them  a  long  time  without  altera- 
tion. We  know  that  chlorine  dissolved  in  water  reacts,  even 
in  diffused  light,  on  this  liquid,  decomposes  it,  appropriates  its 
elements,  and  gives  rise  to  some  compounds  which  possess  an 
action  quite  different  from  that  of  the  chlorine  solution  in  its 


368 


COCHINEAL. 


primitive  state.  The  second  process  seems  to  us  to  be  prefera- 
ble, as  the  proof  liquor  may  be  kept  a  long  while  without 
alteration.  A  graduated  tube  is  also  used  ;  each  division  repre- 
sents one-hundredth  of  the  coloring  matter.  Thus,  the  quan- 
tity of  proof  liquor  added  exactly  represents  the  quantity  in 
hundredths  of  coloring  matter  contained  in  the  decoction  of 
cochineal  which  has  been  submitted  to  examination. 
Another  process  is:  — 

"The  coloring  matter  of  cochineal  being  soluble  in  water, 
I  have  used  this  solvent  for  exhausting  the  different  kinds 
which  I  have  submitted  to  examination  in  the  colorimeter.  I 
operated  in  the  following  manner  :  I  took  a  grain  of  each  of 
the  cochineals  to  be  tried,  dried  at  122°  Fah. ;  I  submitted 
them  five  consecutive  times  to  the  action  of  200  grains  of  dis- 
tilled water  at  water-bath  heat,  each  time  for  an  hour ;  for  every 
200  grains  of  distilled  water  I  added  two  drops  of  a  concen- 
trated solution  of  acid  sulphate  of  alumina  and  of  potash.  This 
addition  is  necessary  to  obtain  the  decoctions  of  the  different 
cochineals  exactly  of  the  same  tint,  in  order  to  be  able  to  com- 
pare the  intensity  of  the  tints  in  the  colorimeter.* 

u  In  order  to  estimate  a  cochineal  in  the  colorimeter,  two 
solutions  obtained,  as  described  above,  are  taken  ;  some  of  these 
solutions  are  introduced  into  the  colorimetric  tubes  as  far  as 
zero  of  the  scale,  which  is  equivalent  to  100  parts  of  the  supe- 
rior scale;  these  tubes  are  placed  in  the  box,  and  the  tint  of 
the  liquids  inclosed  is  compared  by  looking  at  the  two  tubes 
through  the  eye-hole,  the  box  being  placed  so  that  the  light 
falls  exactly  on  the  extremity  where  the  tubes  are.  If  a  differ- 
ence of  tint  is  observed  between  the  two  liquors,  wTater  is  added 
to  the  darkest  (which  is  always  that  of  the  cochineal  taken  as 
type)  until  the  tubes  appear  of  the  same  tint.f  The  number 
of  parts  of  liquor  which  are  contained  in  the  tube  to  which 
water  has  been  added  is  then  read  off;  this  number,  compared 
with  the  volume  of  the  liquor  contained  in  the  other  tube,  a 
volume  which  has  not  been  changed,  and  is  equal  to  100,  indi- 
cates the  relation  between  the  coloring  power  and  the  relative 
quality  of  the  two  cochineals.  And  if,  for  example,  60  parts 
of  water  must  be  added  to  the  liquor  of  good  cochineal,  to 
bring  it  to  the  same  tint  as  the  other,  the  relation  of  volume  of 

*  Care  must  be  taken  not  to  add  to  the  water,  which  serves  to  extract  the 
coloring  matter  from  the  different  cochineals,  more  than  the  requisite  quantity 
of  acid  sulphate  of  alumina  and  solution  of  potash,  because  a  stronger  dose 
would  precipitate  a  part  of  the  coloring  matter  in  the  state  of  lake. 

|  For  diluting  the  liquors,  the  same  water  must  always  be  used  which  has 
served  to  extract  the  coloring  matter  of  the  cochineals  under  examination, 
otherwise  the  darkest  decoction  would  pass  into  violet  as  water  was  added  to 
it  to  bring  back  the  tint  to  the  same  degree  of  intensity  as  that  of  the  decoc- 
tion to  which  it  is  compared. 


COCHINEAL. 


369 


the  liquids  contained  in  the  tubes  will  be  in  this  case  as  160  is 
to  100,  and  the  relative  quality  of  the  cochineals  will  be  repre- 
sented by  the  same  relation,  since  the  quality  of  the  samples 
tried  is  in  proportion  to  their  coloring  power." 

Another  adulteration  of  cochineal  consists  in  taking  part  of 
the  coloring  substance  by  a  rapid  ebullition  in  water,  then 
steeping  the  insects  into  a  concentrated  logwood  or  peachwood 
liquor,  drying,  and  covering  them  with  ground  chalk  or  talc. 

This  adulteration  is  detected  by  means  of  lime-water,  which 
completely  precipitates  the  coloring  matter  of  cochineal,  and 
leaves  the  solution  clear.  If  logwood  or  peachwood  be  pre- 
sent, the  solution  remains  purplish  red  after  the  addition  of 
lime-water. 

Alumina  mordants  produce  with  cochineal  solutions,  crimson 
colors  which  are  very  fine  and  fast;  tin  mordants  give  a 
scarlet  color,  remarkable  for  its  beauty  and  fastness.  Pink  is 
obtained  with  an  alumina  mordant,  but  the  cochineal  is  boiled 
with  ammonia  and  water,  instead  of  water  alone.  The  affinity 
of  cochineal  is  greater  for  wool  than  for  silk. 

Some  of  the  German  chemists,  supposing  that  the  plant  upon 
which  the  insect  feeds  might  be  the  source  of  the  coloring  mat- 
ter, instituted  a  series  of  experiments  to  determine  that  point, 
but  without  success.  The  conclusions  they  came  to  were,  that 
the  animal  economy  plays  a  prominent  part  in  the  formation  of 
the  coloring  matter. 

Carmine  is  manufactured  extensively  in  France,  and  is  used 
for  superior  red  inks,  paints,  and  for  coloring  artificial  flowers. 
It  is  prepared  on  a  large  scale  by  boiling  a  quantity  of  cochi- 
neal in  water  with  soda,  and  then  adding  to  it  a  little  alum, 
cream  of  tartar,  and  the  white  of  eggs,  or  isinglass — which 
separates  the  carmine  as  a  fine  flaky  precipitate.  This  precipi- 
tate is  carefully  collected. 

There  is  something  in  the  production  of  good  carmine  which 
is  not  yet  fully  understood.  It  has  not  yet  been  prepared  in 
this  country  in  the  same  perfection  as  in  France  (page  80).  It 
is  found  also,  that,  with  a  coal  fire,  a  smaller  quantity  of  it  is 
produced  than  when  a  wood  fire  is  employed;  and  there  are 
many  other  little  points  which  show  the  delicacy  of  its  pre- 
paration. 

The  residue  of  the  carmine,  and  some  portions  of  the  pre- 
cipitate from  the  cochineal,  when  first  taken  from  the  fire,  are 
collected  and  boiled  in  water;  to  this  mixture  is  added  a  solu- 
tion of  alum  and  chloride  of  tin,  by  which  a  beautiful  red- 
colored  precipitate  or  lake  is  formed.  This  constitutes  the 
beautiful  pigment  known  as  carmine  lake. 
24 


370 


LAKE  LAKE,  OR  LAC. 


Lake  Lake,  or  Lac, 

Ts  a  concrete  juice  which  exudes  from  several  kinds  of  plants. 
It  appears,  however,  to  be  determined  that  it  is  caused  by  an 
insect  named  coccus  jicus,  or  ccecus  loco,  and  may  therefore  be 
regarded  as  of  animal  origin.  There  are  several  varieties  of 
this  product  under  the  names  of  stick-lac,  seed-lac,  and  shell-lac. 
There  are  also  brought  from  India  two  other  products  dis- 
tinguished as  lac-lac  and  lac-dye — which  are  the  kinds  mostly 
used  in  dyeing,  but  their  composition  is  not  very  well  known. 
They  however  contain  a  goodly  quantity  of  resinous  matter, 
which  must  be  destroyed  before  they  are  put  to  use  as  a  dye. 
Lac-lac  is  obtained  fit  to  use  as  a  dye  by  boiling  the  gum-lac 
with  alkaline  water,  which  dissolves  the  coloring  matter  along 
with  some  of  the  resinous.  To  this  is  added  some  alum,  which 
precipitates  the  whole  as  an  aluminous  product,  in  which  state 
it  is  used. 

Dr.  Bancroft  discovered  that  acids  destroyed  the  resinous 
matter  of  lac  dye,  and  rendered  the  coloring  matter  soluble, 
and  this  is  the  mode  generally  adopted  in  working  with  this 
substance. 

The  following  may  be  taken  as  the  ordinary  means  of  pro- 
ducing this  color:  Add  to  four  pounds  of  lac  dye  three 
pounds  of  strong  sulphuric  acid,  and  set  the  mixture  aside  for 
two  days;  pour  over  it  half  a  gallon  of  boiling  water ;  stir  the 
whole  well,  and  leave  it  to  settle  for  twenty-four  hours ,  the 
clear  liquor  is  then  to  be  decanted  into  a  leaden  vessel,  and 
the  residue  washed  with  water  until  all  the  coloring  matter  is 
dissolved.  The  washings  may  be  added  to  the  liquor  in  the 
leaden  vessel.  There  is  then  added  to  this  liquor  a  quantity 
of  lime-water,  until  the  solution  barely  tastes  acid,  which  pre- 
cipitates the  sulphuric  acid ;  the  whole  is  then  thrown  upon  a 
filter,  and  the  clear  liquor  passing  through  the  filter  forms  the 
dye. 

Some  dyers  take  about  32  parts  of  lac  dye,  and  rub  it  down 
fine  in  10  parts  of  strong  sulphuric  acid;  then  add  three  times 
the  quantity  of  the  mixture  of  water,  and  set  aside  for  two 
days ;  it  is  then  ready  for  use,  requiring  merely  to  be  diluted 
as  required. 

The  French  dyers  generally  take  32  parts  of  lac  dye,  rubbed 
down  in  12  parts  of  hydrochloric  acid  of  30°  Twaddell ;  when 
well  mixed,  it  is  diluted  with  about  an  equal  quantity  of  water, 
set  aside  for  twenty-four  hours,  and  stirred  from  time  to  time  ; 
it  is  then  ready  for  use.  Many  dyers  treat  the  lac-lac  in  the 
same  way  as  the  lac  dye,  using  one  pound  of  sulphuric  acid 


KERMS — MUREXIDE. 


371 


to  two  pounds  of  lac-lac ;  in  other  respects  the  process  is  the 
same. 

The  mordants  employed  for  dyeing  with  the  lacs  are  termed 
lac  spirits ;  the  lac  and  spirits  are  mixed  previous  to  using. 
Lacs  are  employed  as  substitutes  for  cochineal,  and  most  of 
the  colors  obtained  by  the  one  are  producible  by  the  other ; 
but  for  fine  reds  the  lac  is  much  inferior.  This  dye  is  only 
used  for  silk  and  woollens. 


This  is  also  an  animal  substance — the  dried  bodies  of  another 
species  of  the  coccus  insect.  This  insect  is  supposed  to  have 
been  known  as  a  dye  so  early  as  the  time  of  Moses ;  it  was 
used  in  India  at  a  very  early  age,  and  was  highly  valued  both 
by  the  Eomans  and  Spaniards  for  dyeing  purples,  but  after  the 
cochineal  dye  was  discovered,  the  latter  was  used  in  preference, 
on  account  of  the  superior  beauty  of  the  colors.  Accordingly,  in 
many  countries  where  the  kerms  insect  was  reared  and  enriched 
the  people,  the  remembrance  of  it  is  lost. 

Good  kerms  is  of  a  full  deep-red  color,  having  a  pleasant 
smell,  and  sharp  sour  taste;  the  red-coloring  matter  is  soluble 
in  wates  and  in  alcohol.  It  possesses  properties  similar  to 
cochineal. 

Acids  render  it  Yellowish-brown. 

Alkalies  Crimson-violet. 

Iron  salts  turn  it  Black. 

Alum  renders  it  Blood-red. 

Salts  of  tin   A  bright  red. 


For  a  red  with  tin  it  requires  about  12  times  the  quantity  of 
kerms  as  of  cochineal,  and  the  color  is  a  little  inferior.  As  a 
dye,  it  is  not  much  used,  and  only  for  silk  or  woollens.  There 
is  but  little  affinity  between  cotton  and  the  coloring  matters  of 
cochineal,  lacs,  and  kerms. 


Kerms,  or  Kermes. 


Gray-color. 

.  Olive-green. 

.  Cinnamon-brown, 


Sulphate  of  copper  and  tartar  . 
Tin  salts  and  tartar    .    .    .  . 


MUREXIDE. 


This  fine  color,  which  is  considered  as  a  purpurate  of  am- 
monia, had  a  great  success,  as  long  as  aniline  colors  were  not 


372 


MUREXIDE. 


known  ;  the  greater  cheapness  of  the  latter  caused  murexide  to 
fall  into  oblivion. 

Murexide  is  extracted  from  uric  acid,  after  the  transformation 
of  the  latter  into  alloxane;  and  the  operation  requires  a  great 
deal  of  care  and  precision. 

The  uric  acid,  which  is  cheaply  obtained  from  Peruvian 
guano,  is  gradually  thrown  into  nitric  acid,  taking  care  to  pre- 
vent a  too  great  elevation  of  temperature ;  the  mixture  is  then 
allowed  to  cool.  After  24  hours  the  alloxane  crystallizes,  and 
after  separation  from  the  excess  of  acid,  is  made  to  crystallize 
a  second  time  in  water.  The  formula  of  anhydrous  alloxane 
is  C8H4N2O10.  A  solution  of  alloxane  reddens  litmus,  imparts 
a  purple-red  color  to  wool,  and  colors  copperas  an  indigo  blue. 

Carbonate  of  ammonia  is  then  added  drop  by  drop  to  a  boiling 
solution  of  alloxane,  until  the  liquor  has  a  slight  smell  of  am- 
monia. Carbonic  acid  is  evolved,  and  soon  after  there  is  a 
deposit  of  crystals  of  murexide  =  C12H6N5Og.  This  substance 
is  very  slightly  soluble  in  water,  although  it  colors  it  a  deep 
red;  it  is  also  insoluble  in  alcohol  and  ether.  Alkaline  solu- 
tions dissolve  it,  and  are  colored  blue;  but  the  murexide  is 
soon  decomposed  if  heat  is  applied.  Its  aqueous  solution  gives 
with 

Nitrate  of  soda — red  precipitate,  ^ 

Nitrate  of  potassa — brown- red  precipitate,  !    Both  solutions 

Chloride  of  calcium — red,  turning  purple,  f    being  boiling. 

precipitate,  J 
Chloride  of  barium — dark-red  precipitate  ; 
Zinc  salts — gold-yellow  precipitate  ; 
Bismuth — orange  precipitate; 
Bichloride  of  mercury — purple-red  precipitate; 


Fabrics  mordanted  with  mercury  or  lead  salts,  and  plunged 
into  tepid  solutions  of  murexide,  become  dyed  a  fine  purple-red, 
which  may  be  changed  to  violet  by  soap  or  alkalies.  With  zinc 
mordants,  yellow  and  orange  shades  are  obtained.  These  colors 
are  beautiful,  but  without  fastness. 


no  precipitate. 


373 


COLORS  DERIVED  FROM  COAL  TAR. 

The  last  ten  years  have  been  fruitful  in  the  discovery  and 
the  application  to  dyeing  and  calico  printing,  of  a  great  many 
new  dyes  derived  from  coal  tar,  and  known  under  the  cognomen 
of  Aniline  Colors. 

Production  of  Coal  Tar. — The  distillation  of  bituminous 
coals  in  closed  vessels  gives  rise  to  a  variety  of  products,  which 
may  be  classified  as  follows : — 

I.  Gaseous  substances,  forming  what  we  know  under  the 
name  of  illuminating  gas,  and  which  is  a  mixture  of  bicarburet 
and  protocarburet  of  hydrogen,  carbonic  oxide  and  acid,  sul- 
phureted  hydrogen  and  hydro-sulphide  of  ammonium.  These 
latter  impurities  are  more  or  less  removed  by  water,  lime,  and 
copperas,  in  the  process  of  purifying  illuminating  gas. 

II.  Water,  holding  in  solution  ammonia  and  its  carbonate, 
hydrosulphide  and  sulpho-cyanide  of  ammonium  ;  and  from 
which  most  of  the  ammoniacal  salts  used  in  the  arts  are 
extracted. 

III.  Coal  tar,  which  is  a  black,  thick,  and  ill-smelling  sub- 
stance, generally  heavier  than  water,  and  from  which  all  the 
colors  which  form  the  subject  of  this  chapter  are  extracted 
after  various  chemical  transformations. 

IV.  Coke,  or  nearly  pure  carbon,  which  is  left  as  a  residue 
in  the  retort  or  furnace,  and  the  specific  gravity  of  which  is 
variable  with  the  quality  of  bituminous  coal  employed,  and  the 
process  of  carbonization. 

Composition  of  Coal  Tar.— The  carbonization  of  many  or- 
ganic matters,  such  as  wood,  peat,  shales,  &c,  also  produces  tar ; 
but  these  kinds  of  tar  are  poor  in  color-giving  substances,  and, 
at  the  present  time,  coal  tar  from  bituminous  coals  is  the  only 
source  from  which  the  aniline  dyes  are  extracted.  Coal  tar 
is  also  variable  in  its  composition  ;  the  temperature  at  which 
the  carbonization  has  been  effected  has  a  great  influence  on 
the  products.  Indeed,  coal  carbonized  at  a  low  temperature 
may  give  a  tar  lighter  than  water,  but  which  will  contain  less 
benzole  and  naphthaline  than  the  same  coal  carbonized  at  a  high 
temperature. 

Taking  as  a  standard  the  coal  tar  produced  in  the  gas  works, 
we  find  it  a  very  complex  body,  formed  of  a  great  many  sub- 
stances having  acid,  neutral,  and  alkaline  properties,  among 


874 


COLORS  DERIVED  FROM  COAL  TAR. 


which  we  will  notice  those  employed  for  our  subject,  color- 
making. 

Boiling 

Names.  Formulae.     Specific  gravities.     points  (Fahr.). 

Acids  of  coal  tar : — 

Carbolic  or  Phenic,      C12H602  1065  370 

Cresylic,  C14H802  397 

Kosolic,  C24Hl206 

Neutral  substances  of  coal  tar  : — 


o 


Benzole  or  Benzine, 

C12H6 

850 

177 

Toluole, 
Xylole, 

CUH8 

C16H10 

870 

230 

867 

164 

Cumole, 

CisH12 

870 

299 

Cymole, 

861 

341 

Naphthaline, 

C20H8 

1153 

428 

Alkaloids  of  coal 

tar: — 

Picoline,  C12H7N  961  271 

Aniline,  C12H7N  '  1080  360 

Toluidine,  C14H9N  388 

Xylidine,  C16HUN  418 

Cumidine,  C18H13N  952  437 

Cymidine,  C20H15N  482 

Chinoline,  C18H7N  1081  462 

The  acid  substances  can  be  removed  by  caustic  solutions  of 
soda  or  potassa,  and  the  alkaloids  or  basic  substances  by  di- 
luted muriatic  or  sulphuric  acids.  The  neutral  bodies  are  sepa- 
rated by  fractional  distillations. 

Among  all  these  substances,  the  most  useful  for  the  manu- 
facture of  dyes,  are  carbolic  acid,  benzole,  toluole  and  naphtha- 
line ;  the  others  are  found  mixed  with  them  in  greater  or  less 
quantity,  and  their  action  is  comparatively  little  known. 

We  see  also  that  aniline,  toluidine,  &c.,  are  already  formed 
in  the  coal  tar ;  but  their  percentage  is  so  small  that  it  has  been 
found  more  advantageous  to  manufacture  them  directly  from 
the  benzole  and  toluole,  which  are  found  comparatively  in  large 
proportion,  and  are  extracted  by  the  following  processes : — 

Distillation  of  Coal  Tar. — The  tar  is  first  distilled  in 
iron  boilers,  and  the  distillate  is  separated  into  two  portions, 
one  lighter,  and  the  other  heavier  than  water,  and  known  under 
the  name  of  light  oil,  and  heavy  or  dead  oil.  '  What  remains  in 
the  still,  is  a  pitch,  which  is  soft  or  brittle,  according  to  the 
amount  of  dead  oil  distilled  over,  and  which  is  used  for  water- 
proof cements,  rough  varnishes,  the  covering  of  roofs,  &c.  Cer- 
tain kinds  of  oils,  called  green  oils,  on  account  of  their  color, 


ANILINE. 


375 


pass  at  the  end  of  the  distillation,  at  about  700°  Fahr.,  and  are 
used  for  the  manufacture  of  carriage  grease. 

The  dead  oils  are  rich  in  naphthaline,  and  when  newly  pre- 
pared, or  separated  from  the  solid  naphthaline,  are  used  mostly 
for  the  preservation  of  timber,  railroad  ties,  &c,  under  the  not 
very  appropriate  name  of  creosote.  The  solid  naphthaline  may 
be  purified  by  expelling  by  pressure  the  liquid  hydro-carbons 
which  contaminate  it,  and  subliming  it  with  the  addition  of 
some  sand  and  lime,  which  retain  the  last  impurities.  Purified 
naphthaline  is  in  the  form  of  white  and  pearly  scales,  and  is 
submitted  to  various  operations  for  its  transformation  into 
several  dyes. 

The  light  oils  contain  the  benzole,  toluole,  and  part  of  the 
carbolic  acid  of  the  coal  tar,  mixed  with  other  oils  and  impu- 
rities, which  it  is  necessary  to  remove  by  several  fractional  dis- 
tillations by  means  of  steam  or  fire.  By  the  first  operation,  light 
oils  are  separated  into  crude  naphtha,  which  contains  the  ben- 
zole, toluole,  &c,  and  into  other  oils  rich  in  carbolic  acid. 
The  crude  naphtha  is  then  purified  by  treatment  with  oil  of 
vitriol  and  soda,  which  precipitate  and  dissolve  the  tarry  mat- 
ters, and  are  afterwards  distilled  by  steam,  in  order  to  separate 
the  benzole  and  the  toluole.  What  remains  is  the  solvent 
naphtha,  used  for  making  varnishes  and  dissolving  India  rubber. 

The  oils  containing  carbolic  acid  may  be  distilled  over  again, 
collecting  what  passes  between  300°  to  400°  Fahr.  By  shaking 
it  with  a  caustic  solution  of  soda  (1.08  sp.  gr.),  carbolic  acid 
will  be  dissolved,  forming  carbolate  of  soda,  and  the  neutral 
oils  will  float  at  the  surface,  and  will  be  removed.  The  solution 
of  carbolate  of  soda  is  then  neutralized  by  sulphuric  or  muri- 
atic acid,  forming  sulphate,  or  muriate  of  soda  (Na  CI),  and 
the  separated  carbolic  acid  is  purified  by  oil  of  vitriol  and  ano- 
ther distillation.  Carbolic  acid  is  a  powerful  antiseptic,  and  is 
used  for  the  manufacture  of  several  dyes. 

We  have  briefly  seen  how  benzole,  toluole,  carbolic  acid,  and 
naphthaline,  which  are  the  most  important  elements  of  coal  tar 
colors,  are  obtained.  We  shall  pass  now  to  the  production  of 
aniline. 

Aniline. — This  alkaloid  extracted  first  from  indigo,  ^till 
bears  a  name  derived  from  anil,  the  Portuguese  name  of  in- 
digo. Some  years  ago,  it  was  thought  that  pure  benzole  alone 
would  produce  the  best  aniline ;  but  impure  benzoles  having 
given  better  results  in  the  manufacture  of  aniline  dyes,  it  has 
been  ascertained  that  a  certain  proportion  of  toluole  in  com- 
mercial benzoles  or  benzines  was  advantageous,  and  those  con- 
sidered as  such  contain  from  one-fourth  to  one-third  of  toluole. 
We  shall  therefore  consider  under  the  name  of  aniline  a  mix- 
ture of  aniline  and  toluidine. 


376 


ANILINE. 


The  first  step  in  the  manufacture  of  aniline,  consists  in  trans- 
forming the  mixture  of  benzole  and  toluole  into  nitro-benzole 
and  nitro-toluole,  by  the  action  of  fuming  nitric  acid  or  a 
mixture  of  nitric  and  sulphuric  acids.  The  proper  proportion 
of  acid  is  put  into  a  stoneware  or  cast-iron  vessel,  which  can  be 
cooled  off  at  will,  and  the  hydro-carbons  are  run  slowly  into 
it,  stirring  occasionally.  The  reaction  may  be  represented  by 
the  following  formulas: — 

Benzole.  Nitric  acid.  Nitro-benzole. 


C12H6       +       HN06       =       C12H5N04  +  2H0 

Toluole.  Nitric  acid.  Nitro-toluole. 

"CJ3?      +       HN06       -       C^4H7N04  +  2HO 
where  one  equivalent  of  hydrogen  of  the  hydro-carbon  unites 
with  one  of  the  oxygen  of  the  nitric  acid,  and  the  remaining 
peroxide  of  nitrogen  combines  with  the  hydro-carbon.    It  is 
what  is  called  a  transformation  by  oxidation. 

The  nitro-benzole  and  nitro-toluole  produced  are  separated 
from  the  acid  by  a  large  quantity  of  water,  washed  thoroughly 
with  a  diluted  solution  of  carbonate  of  soda,  and  form  the 
commercial  nitro-benzine  or  nitro-benzole. 

It  is  heavier  than  water,  yellow,  has  the  odor  of  bitter  al- 
monds, and  is  soluble  in  alcohol  and  ether. 

The  other  operation  consists  in  reducing  or  deoxidizing  the 
nitro-benzine  or  nitro-toluidine,  that  is  to  say,  by  replacing 
their  oxygen  by  a  certain  amount  of  hydrogen,  as  may  be  seen 
by  these  chemical  figures  : — 

Nitro-benzole.  Aniline. 


C12H4N04  +  6H     =     C12H7N  +  4HO 

Nitro-toluole.  Toluidine. 


C14H7N04  +  6H     =     C14H9N  +  4HO 

This  reduction  can  be  effected  by  several  processes  ;  for  in- 
stance, by  sulphide  of  ammonium,  and  by  nascent  hydrogen. 
But;  iron  turnings  and  strong  acetic  acid,  as  devised  by  Mr. 
Bechamp,  have  been  found  the  most  advantageous  in  practice. 
The  reaction  may  be  expressed  thus: — 

Nitro-benzole.  Aniline. 

c72H5NO^  +  4Fe  +  2HO  =  C^H.N  +  2(Fe203) 

Nitro-toluole.  Toluidine. 

c74H7N04  +  4Fe  +  2HO  =  C^N"  +  2(Fe203) 


THEORY  OF  ANILINE  COLORS. 


377 


One  part  of  commercial  nitro-benzole  is  mixed  with  one  part 
of  strong  acetic  acid,  to  which  is  added  1^  part  of  iron  turnings. 
The  operation  is  made  in  an  iron  cylinder,  furnished  with  a 
stirring  apparatus,  and  a  condenser.  When  the  transforma- 
tion is  complete,  heat  is  applied,  and  the  whole  is  distilled,  ex- 
cept the  peroxide  of  iron  which  remains  in  the  retort.  The 
crude  aniline  is  treated  with  a  little  soda  or  lime,  and  distilled 
over  again. 

The  aniline  thus  produced  is  a  mobile  oil,  colorless  when 
pure,  and  difficult  to  freeze.  Its  specific  gravity  is  1.020,  and 
it  boils  at  360°  Fahr.  It  emits  vapors  at  the  ordinary  tem- 
perature of  the  atmosphere,  and  burns  with  a  large  smoky 
flame.  Slightly  soluble  in  water,  its  true  solvents  are  alcohol, 
ether,  &c.    It  forms  salts  with  acids. 

Much  of  what  we  have  said  about  aniline  may  be  applied  to 
toluidine. 

Aniline  is  also  considered  as  an  amide  of  the  organic  radical 
phenyl,  as  may  be  seen  by  this  equation : — 

Aniline.  Phenyl  amide. 

c^n    =  cwiy* 

Theory  of  Aniline  Colors. — Although  the  remarkable 
researches  of  MM.  *A.  W.  Hofmann,  Grirard,  and  de  Laire,  &c, 
have  shed  much  light  on  the  composition  of  aniline  colors,  we 
cannot  say  that  there  is  at  the  present  day  a  true  theory  of 
these  colors,  that  is  to  say,  a  theory  which  answers  entirely  all 
cases,  and  explains  satisfactorily  all  the  transformations. 

Three  opinions  are  now  held  :  1st,  aniline  or  toluidine  alone 
cannot  produce  colors,  while  their  mixture  will ;  2d,  aniline  or 
toluidine  will  each  of  them  give  colors;  3d,  toluidine  alone  is 
the  source  of  the  colors,  but  requires  the  presence  of  aniline 
for  their  production. 

All  the  aniline  colors  appear  to  be  due  to  various  degrees  of 
oxidation  of  this  alkaloid,  when  submitted  to  oxidizing  agents. 
For  instance,  a  solution  of  hypochlorite  of  lime  (bleaching 
powder)  gives  it  a  bluish-purple  color.  Bichromate  of  potassa 
or  peroxide  of  manganese,  &c,  and  some  sulphuric  acid,  pro- 
duce in  a  solution  of  sulphate  of  aniline,  green,  blue  and  black 
colors.  Nascent  oxygen,  as  produced  by  the  galvanic  decom- 
position of  water,  will  also  act  on  aniline.  For  this  experiment, 
the  aniline  is  dissolved  in  water  acidulated  with  a  little  sulphuric 
acid,  and  at  the  platinum  pole,  where  oxygen  is  evolved,  will 
be  seen  a  green  coloration,  which  will  turn  blue,  violet,  and 
finally  red,  showing  the  influence  of  more  or  less  oxidation. 

The  processes  employed,  as  well  in  experimental  researches, 


378 


THEORY  OF  ANILINE  COLORS. 


as  in  the  manufactures,  for  the  production  of  aniline  or  coal 
tar  colors,  are  all  based  on  methods  of  oxidation,  reduction,  and 
substitution,  of  the  organic  substances  under  treatment. 

We  have  already  seen  examples  of  oxidation,  where  the  sub- 
stance acted  upon  is  made  to  gain  a  certain  amount  of  oxygen, 
or  more  generally  to  lose  part  of  its  hydrogen ;  and  of  reduc- 
tion, in  the  transformation  of  nitro-benzole  and  nitro-toluole 
into  aniline  and  toluidine. 

The  methods  of  substitution  consist  in  replacing  certain  or- 
ganic groups  by  other  groups  called  organic  radicals,  such  as 
phenyl,  methyl,  &c. 

A  great  many  substances  occasion  transformations  by  oxi- 
dation and  reduction.  The  following  are  employed  in  the 
manufacture  of  coal  tar  colors. 

I.  Oxidizing  agents : — 
Oxygen,  air,  ozone ; 

Nitric  acid,  nitrous  oxides,  nitrates  ; 

Chlorine,  bleaching  powders  or  liquids,  chlorates ; 

Bromine,  iodine  ; 

Cyanoferride  of  potassium  (red  prussiate) ; 

Arsenic  acid,  arseniates  ; 

Ammonia,  with  oxygen  or  air ; 

Chromic  acid,  bichromates  with  sulphuric  acid  ; 

Permanganic  acid,  permanganates; 

Peroxides  of  manganese,  lead,  antimony,  &c. ; 

Sulphide  of  copper,  &c.  &c. ; 
which  give  up  part  of  their  oxygen,  or  attract  this  gas,  or  cause 
its  production. 

II.  Eeducing  agents  : — 

Nascent  hydrogen,  sulphureted  hydrogen  ; 
Sulphurous  acid,  sulphites  and  hyposulphites; 
Cyanides,  sulpho-cyanides ; 
Salts  of  protoxide  of  iron ; 

tin  ; 

Aldehyd,  &c.  &c. ; 
which  have  a  great  attraction  for  oxygen,  or  fix  a  certain 
amount  of  carbon  or  hydrogen  on  organic  molecules. 

We  shall  see  further  on,  that  by  varying  the  proportion  of 
these  reagents,  the  length  of  the  operation,  and  the  tempera- 
ture, various  shades,  or  if  we  may  say  so,  various  degrees  of 
oxidation  or  reduction,  may  be  obtained. 

By  their  transformation  into  colors,  the  alkaloids  we  have 
examined,  aniline,  toluidine,  &c,  form  different  bases,  which 
have  been  examined  by  MM.  A.  W.  Hofmann,  Girard,de  Laire, 
and  Chapoteaut,  and  whose  composition  and  hypothetical  mode 
of  formation  are  as  follows : — 


THEORY  OF  ANILINE  COLORS. 


379 


Violaniline.  Aniline. 

c"36H15N^=  3(C12H7N)-6H 

Mauvaniline.  Aniline.  Toluidine. 

C3SH17N^  =  2(CI2H7N)  +  CJH^-6H 

Rosaniline.         Aniline.  Toluidine. 

'cj^N,  -  C^N  +  2(C^iXn)-6H 

Chrysotoluidine.  Toluidine. 

G^PJH,  -  3(O^N)-6H 

These  bases  unite  with  acids,  and  form  well  crystallized  salts 
which  have  a  great  tmctorial  power. 

Under  the  influence  of  reducing  agents,  such  as  nascent 
hydrogen,  the  base  rosaniline  dissolved  in  muriatic  or  sulphuric 
acid,  in  which  some  zinc  is  added,  is  transformed  into 

Leucaniline,  Rosaniline. 


C40H21N3  =  C40H19N3  +  2H 

which  is  colorless  itself,  and  gives  colorless  salts.  Exposure  to 
the  air  will,  by  means  of  oxidation,  restore  the  original  colored 
salt  of  rosaniline.  Leucaniline  is  soluble  in  alcohol,  and 
scarcely  in  cold  water. 

Another  base  extracted  from  the  waste  product  of  rosaniline 
is  chrysaniline  =  040H17N3,  and  is  freely  soluble  in  water,  when 
combined  with  hydrochloric  acid. 

The  aniline  blues  and  violets  present  examples  of  substitu- 
tion, where  three  atoms  of  typic  hydrogen  are  replaced  by  the 
organic  radicals,  phenyl,  methyl,  ethyl,  &c. 

For  instance,  aniline  blue  is  a  triphenylic  rosaniline — 

—  C!      i       ^"l6     1 1ST  • 

-  0«   }3(C12H4)  r»' 

Aniline  violet  (blue  shade)  is  a  diphenylic  rosaniline — 

=  c«  {2(0%}^; 

And  aniline  violet  (red  shade)  is  a  monophenylic  rosaniline — 


Until  now,  we  have  examined  substances  which  accord  with 
the  rules  of  our  theory ;  but  the  base,  mauveine,  discovered  by 
Mr.  W.  H.  Perkin,  has  a  composition  quite  different,  as  may  be 


880 


ANILINE  REDS. 


seen  by  its  formula — C54H24N4,  and  which  does  not  agree  with 
the  above  rules.  This  base,  which  has  been  obtained  perfectly- 
pure  in  the  crystallized  state,  is  different  from  all  aniline  bases 
by  forming  a  salt  with  carbonic  acid. 

Aniline  Eeds. — We  begin  with  these  dyes,  because  they 
are  the  salts  of  rosaniline,  from  which  we  derive  most  aniline 
colors.  We  cannot  help  seeing  a  certain  analogy  in  the  pro- 
cesses of  manufacture  of  these  colors  and  those  of  the  compounds 
of  carbon  and  iron.  To  make  steel  we  partially  decarburize 
pig-metal,  or  carburize  iron  to  a  certain  point ;  here,  in  many 
cases,  we  also  partially  deoxidize  rosaniline,  or  oxidize  aniline 
to  a  certain  point.  We  mix  pig-metal  with  iron  in  order  to 
produce  a  certain  steel,  we  also  mix  rosaniline  salts  with  aniline 
to  make  a  certain  color.  Pig-iron  is  the  most  carburized  iron; 
rosaniline  is  the  most  oxidized  aniline. 

Aniline  red,  under  the  name  of  fuchsine,  or  magenta,  was  ob- 
tained first,  on  a  practical  scale,  by  heating  together  aniline  and 
anhydrous  bichloride  of  tin  ;  a  hydrochlorate  of  rosaniline  is 
thus  formed.  Sulphate  of  aniline  and  binoxide  of  lead,  nitrate 
of  peroxide  of  mercury  and  aniline  were  also  used  ;  but,  at  the 
present  day,  aniline  is  peroxidized  or  dehydrogenated  by  means 
of  arsenic  acid.  Into  a  cast-iron  vessel,  which  can  be  heated 
on  a  paraffin  bath,  is  poured  a  mixture  of  20  parts  by  weight 
of  syrupy  arsenic  acid,  containing  76  per  cent,  of  the  solid 
acid,  and  12  parts  of  commercial  aniline.  An  arseniate  of 
aniline  is  formed,  wrhich,  by  an  elevation  of  temperature  is 
transformed  into  rosaniline  and  arsenious  acid.  During  the 
whole  operation  the  mass  is  constantly  stirred.  The  molten  mass 
is  then  mixed  with  some  water,  run  into  a  boiler,  boiled  with 
steam  to  remove  the  impurities,  and  filtered.  By  adding  lime 
to  the  solution,  rosaniline  is  precipitated  with  the  insoluble  ar- 
senite  of  lime  produced,  and  may  be  dissolved  in  acetic  acid. 
This  being  expensive,  it  is  better  to  add  common  salt  to  the 
solution  ;  hydro-chlorate  of  rosaniline  and'arsenite  of  soda  are 
formed,  by  double  decomposition,  and  the  former  salt  being 
insoluble  in  a  concentrated  saline  solution,  rises  to  the  surface 
and  is  collected.  By  re-crystallization  a  very  pure  hydro- 
chlorate  of  rosaniline  is  formed,  which  can  be  used  in  this  state. 

Rosaniline  may  be  precipitated  by  saturating  the  hydro- 
chloric acid  by  caustic  soda  or  lime,  and,  if  pure,  is  colorless. 
It  is  not  very  soluble  in  water,  and  is  used  for  making  other 
salts. 

Azaleine,  rubine,  often  designated  under  the  name  of  magenta, 
are  nitrates  of  rosaniline, 

Roseine  is  the  acetate  of  the  same  base. 

Eosaniline  is  not  the  only  base  produced  during  the  treat- 


ANILINE  BLUES  AND  VIOLETS. 


381 


ment  with  arsenic  acid ;  other  basic  substances  are  formed,  and 
found  in  the  residues;  such  are:  Mauvaniline,  chrysaniline, 
and  chrysotoluidine,  of  which  we  have  given  the  formulae. 

Aniline  Blues  and  Violets. — An  aniline  violet  was  the 
first  aniline  color  manufactured.  Discovered  by  Mr.  Perkin, 
in  1857,  it  is  a  sulphate  of  mauveine,  known  under  the  name 
of  Mauve,  Indisine,  &c,  and  produced  by  oxidizing  sulphate  of 
aniline  by  bichromate  of  potassa.  Tarry  substances  are  formed 
at  the  same  time,  which  are  removed  by  dissolving  them  in 
hydrocarbons,  such  as  naphtha.  This  violet  or  purple  is  hardly 
soluble  in  water,  but  easily  so  in  alcohol  and  sulphuric  acid. 

Chloride  of  lime  made  to  oxidize  a  salt  of  aniline,  produces 
also  this  same  color,  taking  care  to  stop  the  operation  when 
the  desired  shade  has  appeared.  Chlorine,  peroxide  of  manga- 
nese, &c,  with  a  salt  of  aniline,  give  similar  results.  The  varia- 
tions in  the  quality  and  the  quantity  of  product,  result  from  the 
proportion  of  reagents  employed,  the  length  of  the  operation, 
and  the  temperature  applied. 

In  the  above  processes,  aniline  has  been  partially  oxidized ; 
in  the  following  ones,  the  most  oxidized  compounds  are  brought 
to  a  lesser  degree  of  oxidation. 

The  Imperial  purple  of  MM.  Girard  and  de  Laire  is  obtained 
by  heating  together  a  salt  of  rosaniline,  magenta,  for  instance, 
with  its  own  weight  of  aniline,  at  a  temperature  of  350°  Fah., 
and  for  several  hours.  All  the  unaffected  aniline  is  removed 
by  weak  acids,  and  the  purple  remains. 

The  Regina  purple  of  Mr.  Nicholson  is  magenta  heated  to  a 
temperature  of  390°  to  420°  Fah.;  the  substance  melts,  evolves 
ammonia,  and  the  new  color  is  produced. 

Blues  can  be  obtained  from  these  violets,  by  washing  them 
several  times  with  diluted  hydrochloric  acid,  in  order  to  dis- 
solve all  the  aniline  and  magenta  undecomposed,  and  also  a 
violet  color.  Aniline  blues  generally  contain  some  violet,  and 
the  violets  some  red  shades  in  them. 

We  find  in  the  trade,  blues  with  violet  shades,  and  violets 
with  red  or  blue  shades.  Repeated  washings  will  remove  the 
violet,  which  is  more  soluble  than  the  blue.  But  we  must  not 
consider  the  violets  as  simple  mixtures  of  blue  and  red;  the 
different  shades  are,  as  we  have  already  seen,  salts  of  rosani- 
line  in  which  part  of  the  hydrogen  has  been  replaced  by  the 
radical  phenyl.  By  varying  the  proportions  of  magenta  and 
aniline,  and  also  the  temperature,  various  shades  of  violet  are 
obtained. 

A  true  blue  is  prepared,  by  adding  to  the  mixture  of  magenta 
and  aniline,  an  organic  acid  or  salt,  such  as  benzoic,  acetic  acid, 
or  acetates.   The  blues  thus  obtained,  are  called  Bleu  de  nuit, 


882 


ANILINE  YELLOWS. 


Night  blue,  Bleu  lumilre,  on  account  of  remaining  blue  under 
artificial  light. 

Hofmanrfs  blues  and  violets,  known  also  under  the  name  of 
Iodine  blues  and  violets,  have  been  obtained  by  this  chemist  in 
replacing  three  equivalents  of  hydrogen  in  rosaniline  by  the 
radical  ethyl  =  C4H5  in  the  presence  of  iodine. 

The  blue  color  formed  is  a  tri-ethylic  rosaniline,  whose 
formula 

To  manufacture  this  salt— one  part  of  magenta,  two  parts  of 
iodide  of  ethyl,  and  about  two  parts  of  strong  methyl  or  ethyl 
alcohol  are  heated  in  a  close  vessel  (cast  iron  enamelled,  or  lined 
with  lead),  at  a  temperature  a  little  above  212°  Fah.,  for  three 
to  four  hours. 

These  blues  and  violets  are  soluble  in  alcohol,  not  in  water ; 
but  they  may  be  rendered  soluble  in  water  by  withdrawing 
the  iodine.  An  alkali  heated  with  the  dye,  dissolves  the  iodine, 
and  the  insoluble  coloring  matter,  after  washing,  is  dissolved  in 
muriatic  acid.  By  this  operation,  there  is  a  double  gain : 
first,  saving  the  iodine;  secondly,  avoiding  the  use  of  alcohol 
for  dyeing. 

For  aniline  blues  and  violets,  a  certain  mixture  of  aniline 
and  toluidine  is  not  so  indispensable  as  in  the  manufacture  of 
aniline  reds.  In  these  substitution  compounds,  toluidine  gives 
blues  by  another  radical,  tolyl  =  C14H7,  taking  the  place  of 
three  equivalents  of  hydrogen.  The  toluidine  blues  are  more 
soluble  than  those  of  rosaniline. 

The  iodides  of  methyl,  amyl,  propyl,  &c,  may  be  used  instead 
of  the  iodide  of  ethyl. 

Eeducing  agents,  such  as  nascent  hydrogen,  will  transform 
the  salts  of  ethyl  or  phenyl-rosaniline,  into  colorless  salts  of 
ethyl  or  phenyl-leucaniline. 

Aniline  Yellows. — Under  the  name  of  phosphine,  aniline 
yellows,  victoria  orange,  chrysaniline  yellow,  the  chrysaniline,  which 
we  have  already  noticed  in  the  secondary  products  of  the 
manufacture  of  aniline  reds,  is  employed  for  dyeing,  combined 
with  muriatic  or  acetic  acid. 

Mr.  Vogel  discovered  a  new  dye,  which  he  calls  zinaline,  by 
treating  a  solution  of  magenta  in  water,  by  nitrous  acid  (N03). 

We  have  also  chrysotoluidine  yellow,  which  is  found  associated 
with  violaniline  and,  mauvaniline,  in  the  manufacture  of  hydro- 
chlorate  of  rosaniline. 

Aniline  Orange  has  been  extracted  from  the  residues  of  the 
manufacture  of  nitrate  of  rosaniline. 


ANILINE  GREENS. 


383 


Aniline  Greens. — Those  who  have  worked  the  aniline  salts 
in  laboratories,  have  frequently  seen  green  efflorescences  on 
vessels  containing  these  salts.  The  coloration  was  generally 
due  to  atmospheric  oxidation,  and  great  difficulty  has  been 
experienced  in  fixing  that  color;  happily,  chance  helped  the 
constancy  of  the  investigators. 

Aldehyd  green,  aniline  green,  night  green,  vert  lumifoe,  &c,  are 
obtained  by  treating  4  parts  of  magenta,  by  6  of  oil  of  vitriol, 
and  2  of  water.  Then  16  parts  of  aldehyd  are  added,  and 
the  whole  is  kept  at  the  temperature  of  boiling  water,  until  a 
few  drops  of  the  liquid  give  a  blue  color  to  a  weak  solution 
of  sulphuric  acid.  The  liquid  is  then  poured  into  a  solution  of 
hyposulphite  of  soda,  and  the  green  is  "fixed,"  as  photographers 
say. 

This  green  bath  can  be  used  directly  for  dyeing;  it  does  not 
keep  very  long,  but  the  color  may  be  precipitated  by  tannin  or 
acetate  of  soda.  The  insoluble  compound  is  employed  for  calico 
printing,  or  forming  new  dye  baths. 

An  iodide  of  ethyl  green  is  produced  by  boiling  Hofmann's 
violet  with  water  and  carbonate  of  soda.  The  filtered  liquor 
is  treated  by  picric  acid,  a  green  precipitate  is  formed  which 
is  washed,  dried,  and  sold  in  powder.  It  is  soluble  in  alcohol, 
&nd  we  believe  in  water,  after  trituration  of  the  powder  with 
two  or  three  times  its  weight  of  sal  ammoniac. 

There  are  also  rosaniline  and  toluidine  greens. 

By  the  aldehyd  process,  rosaniline,  or  the  most  oxidized  pro- 
duct of  aniline,  has  been  "reduced"  to  green.  The  emeraldine  of 
MM.  F.  C.  Calvert,  Lowe  and  Clift,  is,  on  the  other  hand,  a  pro- 
cess of  oxidation  of  aniline  by  chlorate  of  potassa.  This  new 
process  has  what  is  remarkable,  in  common  with  aniline  black, 
which  we  shall  examine  further  on,  that  the  production  of  the 
color,  or  the  oxidation  of  the  aniline  salt,  is  effected  upon  the 
dyed  or  printed  fibre  itself,  and  that  it  succeeds  better  on  cotton 
goods;  while  all  other  aniline  colors  have  a  greater  affinity 
for  animal  fibres,  than  for  vegetable  ones. 

To  produce  emeraldine,  the  cotton  fabric  is  prepared  with 
113  grains  of  chlorate  of  potassa  per  imperial  gallon,  and  printed 
with  a  mixture  of  3  lbs.  of  tartrate  or  hydrochlorate  of  aniline, 
6  lbs.  of  starch-paste,  and  1  of  chlorate  of  potassa.  The  salt  of 
aniline  is  added  to  the  cold  mixture  of  the  two  other  substances. 

After  a  few  hours  in  the  ageing  room,  a  bright  green  gradu- 
ally appears,  which  is  then  washed.  If  the  green  fabric  is 
passed  through  a  solution  of  bichromate  of  potassa,  the  color 
is  transformed  into  a  dark  indigo  blue,  called  azurine,  and  which 
is  the  result  of  a  further  oxidation  of  the  green  color.  This 
green  turns  blue  by  the  action  of  soap  or  alkalies,  but  acids 
restore  the  primitive  color. 


384  ANILINE  BLACKS  AND  GRAYS. 


Aniline  Blacks  and  Grays.  The  same  as  for  emeraldine 
green,  these  colors  are  developed  upon  the  cotton  fibre  itself. 
Mr.  Lightfoot,  who  discovered  the  aniline  black,  if  black  is  a 
color,  used  a  paste  composed  of  chlorate  of  potassa,  hydro- 
chlorate  of  aniline,  sulphate  or  chloride  of  copper,  and  starch 
enough  to  thicken.  By  the  mutual  oxidizing  reaction  of  chlorate 
of  potassa  and  chloride  of  copper,  the  aniline  is  oxidized  to  the 
degree  of  black.  This  paste  was  open  to  the  objection  of  destroy- 
ing rapidly  the  steel  scrapers  of  the  printing  rollers,  on  account 
of  the  presence  of  a  large  quantity  of  a  salt  of  copper. 

Further  experiments  made  by  MM.  Cordillot,  C.  Kcechlin 
and  Lauth,  led  to  these  important  facts,  viz:  that  the  hydro- 
chlorate  or  nitrate  of  aniline  are  the  only  aniline  salts  which 
can  produce  a  black  ;  that  the  best  aniline  ought  to  be  a  mix- 
ture of  aniline  and  toluidine;  that  the  presence  of  copper  is 
indispensable;  and  that  a  sulphide  of  copper,  prepared  by 
precipitation,  will  not  corrode  the  steel  parts  of  the  printing 
machine,  and  will  gradually  absorb  the  quantity  of  oxygen  for 
its  transformation  into  sulphate. 

If  a  tartrate  or  acetate  of  aniline  is  used,  it  is  necessary  to 
add  to  the  mixture  a  certain  quantity  of  sal  ammoniac,  which 
will  furnish  the  muriatic  acid  necessary  for  the  transformation 
of  the  tartrate  or  acetate  of  aniline  into  a  hydrochlorate.  With 
these  data,  a  good  printing  paste  is  made  by  mixing  together, 
when  cold,  the  two  following  mixtures,  made  separately : — 

I.  — Heat  and  digest  in  water  . 

Starch  

Precipitated  sulphide  of  copper 

II.  — Water     .       .       .       .  . 

Torrefied  starch 
Solution  of  gum  tragacanth  . 
Hydrochlorate  of  aniline 
Sal  ammoniac        .   ,  . 
Chlorate  of  potassa 

For  dyeing  cotton  or  silk,  M.  Cam.  Kcechlin  proposes  a  bath  of 

Water       ....        20  to  30  parts. 
Chloride  of  potassa    .       .  .    1  " 

Sal  ammoniac  .  .  .  .  .  1  u 
Chloride  of  copper     .       .       .       .    1  " 

Aniline  2  " 

Hydrochloric  acid      .       .       .       .    2  " 

The  drying  is  made  in  ageing  rooms,  and  the  color  appears 
at  its  true  shade  only  after  washing. 

The  oxidation  is  such,  that  if  the  goods  dyed  or  printed  were 


50 

parts. 

100 

U 

25 

(( 

185 

it 

120 

u 

100 

a 

80 

« 

10 

u 

30 

u 

COLORS  DERIVED  FROM  CARBOLIC  OR  PHENIC  AGID.  385 

A> 

left  wet  andTolded,  or  in  heaps,  there  would  be  danger  of  spon-  ^ 
taneous  combustion.    Hence  the  necessity  of  drying  immedi- 
ately. 

Aniline  grays  are  obtained  by  diminishing  the  proportion  of 
the  black  producing  substances  of  the  above  receipts,  but  keep- 
ing as  much  free  acid  as  in  the  primitive  mixture  for  black. 

The  Mauveine  gray  of  Mr.  J.  Castelhaz  is  mauveine  blue 
"reduced"  by  aldehyd  in  the  presence  of  sulphuric  acid. 

Mureine  grays  of  different  shades  are  produced  by  MM.  F. 
Carves  &  Thirault,  of  St.  Etienne,  by  treating,  in  various 
proportions,  hydrochlorate  of  aniline  by  a  mixture  of  bichro- 
mate of  potassa,  an  iron  salt,  water,  and  sulphuric  acid.  These 
grays  are  soluble  in  boiling  water,  and  are  employed  in  the 
same  way  as  the  majority  of  aniline  colors. 

Aniline  Browns  and  Maroons. — The  brown  maroon  of  Mr. 
de  Laire  is  made  by  melting  4  parts  of  anhydrous  hydrochlo- 
rate of  aniline  with  1  of  dry  aniline  oil,  the  temperature  being 
slowly  raised  up  to  465°  Fah.  The  operation  is  over  when 
yellow  vapors  begin  to  appear,  and  the  mass  is  suddenly  trans- 
formed into  brown.    The  color  is  soluble  in  water. 

Leucaniline  brown  is  obtained  by  Mr.  Horace  Koechlin  in  the 
following  way:  A  salt  of  rosaniline  is  transformed  into  leu- 
caniline by  zinc  powder.  The  leucaniline  is  separated  from 
the  zinc  by  alcohol,  and  this  being  evaporated,  a  tartrate  of 
leucaniline  may  be  formed,  which  is  afterwards  transformed 
into  brown  by  the  oxidizing  action  of  a  mixture  of  sulphide  of 
copper  and  chlorate  of  potassa. 

Another  aniline  brown  is  made  by  boiling  a  concentrated  solu- 
tion of  chromate  of  ammonia  with  aniline,  and  adding  formic 
acid.    This  operation  is  somewhat  expensive. 


Colors  Derived  from  Carbolic  or  Phenic  Acid. 

We  have  already  seen  how  carbolic  or  phenic  acid  wa£  ex- 
tracted from  coal-tar.  If  aniline  is  an  amide  of  the  radical 
phenyl,  and  is  sometimes  called  phenylamine,  phenic  acid  is  also 
closely  related  to.it,  being  an  oxide  of  phenyl=C12H50.  More- 
over, the  aniline  found  already  formed  in  the  coal-tar,  proceeds 
from  the  reaction  of  phenic  acid  upon  the  ammonia  which  is 
always  produced  by  the  decomposition  of  bituminous  coals. 
The  reaction  takes  place  by  an  elevation  of  temperature,  or 
pressure,  or  both,  and  is  as  follows: — 

Ammonia.     Phenic  Acid.    Aniline.  Water. 


NH40   +  C12H50  =  C]2H7N  +  2H0. 

25 


386     COLORS  DERIVED  FROM  CARBOLIC  OR  PHENIC  ACID. 


For  these  reasons,  we  prefer  the  name  of  phenic  acid  to  that 
of  carbolic,  which  does  not  bear  any  relation  to  the  radical 
phenyl=C12H5.  > 

Phenic  acid,  partially  oxidized,  gives  rise  to 


The  operation  is  performed  by  MM.  Guinon,  Mamas  &  Bon- 
net of  Lyons,  by  heating  together  23  parts  of  phenic  acid  with 
10  to  20  of  oxalic  acid,  and  7  to  14  of  oil  of  vitriol.  The  rosolic 
acid  produced  is  insoluble  in  water,  and  affords  only  very  fugi- 
tive red  shades  upon  fabrics. 

The  Peonine  or  Coralline,  discovered  by  Mr.  J.  Persoz,  is  the 
product  of  the  reaction  of  ammonia  on  rosolic  acid,  heated 
together  in  closed  vessels  at  a  temperature  of  300°  Fah.  This 
red  dye  is  soluble  in  alcohol,  alkaline  solutions,  acetic  acid,  &c. 
It  is  not  very  fast,  and  is  acted  upon  by  sulphurous  acid. 

Azuline  is  a  blue  dye  formed  by  heating  together  5  parts  of 
coralline  with  6  to  8  of  aniline. 

Picric  acid,  Carboazotic  acid  or  Trinitrophenic  acid  is  the  result 
of  the  oxidation  of  picric  acid  by  nitric  acid,  and  has  for  its 
formula : — 


It  dyes  animal  fibres  yellow,  with  a  slight  green  tinge.  The 
picrates  sold  under  the  name  of  picric  acid  or  that  of  aniline 
yellow  should  be  discarded,  as  they  are  highly  explosive,  and 
do  not  dye  as  well  or  so  much  as  pure  picric  acid.  It  is  suffi- 
ciently soluble  in  water  for  dyeing. 

Isopurpuric  acid  is  made  by  adding,  gradually,  a  solution  of 
picric  acid  to  another  solution  of  cyanide  of  potassium.  Am- 
monia and  prussic  acid  are  evolved,  and  purpuric  acid  crystal- 
lizes when  the  liquor  is  cold.  Under  the  name  of  soluble  ruby, 
are  sold  isopurpurates  of  potassa,  or  ammonia,  which  dye  red 
like  murexide.  The  latter  salt  dyes  silk  and  wool  mordanted 
with  corrosive  sublimate  a  magnificent  purple,  and  a  beautiful 
yellow  with  zinc  mordants.  The  colors  are  fast,  except  against 
sulphurous  acid  fumes. 

All  the  salts  formed  by  isopurpuric  acid  detonate  freely 
when  dry ;  they  should  therefore  be  sold  and  kept  in  paste; 
with  an  addition  of  glycerin  for  greater  security. 

Picric  acid  greens  are  made  by  dyeing  with  a  mixture  of  ani- 
line blue  and  picric  acid,  which  appears  grayish  under  artificial 
light;  by  picric  acid  and  carmine  of  indigo  ;  and  by  picric  acid 
and  Prussian  blue,  which  remains  green  under  artificial  light. 

Phenicienne,  or  Rothine,  from  the  discoverer,  Mr.  J.  Roth,  is 


Rosolic  Acid.      Phenic  Acid. 


C24Hl2Oa  =  2(C12HA)  +  20. 


COLORS  DERIVED  FROM  NAPHTHALINE.  387 


the  result  of  the  action  of  azoto-sulphuric  acid  upon  phenic 
acid.  It  is  a  brown  color,  little  soluble  in  water,  but  very 
soluble  in  alcohol,  acetic  acid,  and  alkalies.  It  dyes  fast  colors, 
whose  shade  varies  with  the  mordants  employed,  but  does  not 
bear  well  the  steaming  process. 

Aniline  or,  Picric  acid  broivn,\s  obtained  by  Mr.  E.  Jacobsen, 
by  gradually  heating  up  to  302°  Fah.  1  part  of  picric  acid  and 
2  of  aniline.  Ammonia  is  evolved.  This  color  is  soluble  in 
alcohol  with  an  addition  of  sulphuric  acid  or  glycerine. 

Colors  Derived  from  Naphthaline. 

We  have  seen  at  the  beginning  of  this  chapter  how  naphtha- 
line may  be  extracted  from  coal  tar.  This  substance,  which  has 
been  the  subject  of  such  profound  study  by  Laurent,  and  was 
suggested  by  that  chemist  as  being  a  source  of  coloring  sub- 
stances, has  been  again  submitted  to  many  experiments  since 
the  success  of  aniline  colors.  A  quantity  of  dyes  have  already 
been  discovered,  but  most  of  which,  not  being  fast,  have  been 
abandoned.  This  is  to  be  regretted,  because  naphthaline  can 
be  had  much  cheaper  than  benzole  or  toluole.  Nevertheless, 
we  think,  this  want  of  success  will  be  overcome.  A  very  near 
approach  to  the  artificial  production  with  naphthaline  of  alizarin, 
the  coloring  principle  of  madder,  has  been  made  by  Mr.  Z. 
Eoussin. 

Naphtha lamine,  or  Naphthylarnine,  is  to  naphthaline  what  ani- 
line is  to  benzole,  and  is  obtained  by  similar  processes.  Heated 
with  arsenic  acid,  or  nitrate  of  mercury,  it  produces  fine  purples, 
which  are  insoluble  in  water,  but  soluble  in  alcohol,  and  would 
have  been  used  in  dyeing,  had  they  been  fast. 

Blue  colors  have  also  been  obtained. 

No phthylamine  yellow — JauneoVor — Manchester  yellow,  is  a  mag- 
nificent yellow  prepared  by  treating  the  hydrochlorate  of  naph- 
thylamine  by  nitrite  of  soda,  and  afterwards  with  nitric  acid. 
Dr.  C.  A.  Martius,  the  discoverer,  considers  this  substance  as 
an  acid  analogous  to  picric  acid,  and  calls  it  binitro-naphthylic 
acid.  It  is  superior  to  picric  acid,  the  shades  being  pure  yel- 
low, and  supporting  well  the  steaming  process. 

Chloroxynaphihalate  of  ammonia,  according  to  Mr.  Perkin, 
dyes  silk  a  gold  yellow,  which  stands  light  very  well.  This 
salt  is  very  soluble  in  water. 

Chloroxynaphthalic  acid=C10  H5  C103  is  sufficiently  soluble  in 
boiling  water  for  dyeing  purposes.  It  dyes  wool  a  deep  red? 
without  mordants.  It  is  too  acid  to  be  used  for  cotton.  If 
the  wool  has  been  previously  dyed  with  sulphate  of  indigo,  a 
fine  black  will  appear.  The  sulphate  of  indigo,  may  also  be 
mixed  directly,  with  the  chloroxynaphthalic  acid. 


388         REMARKS  IN  GENERAL  ON  COAL  TAR  COLORS. 


Eemarks  in  General  on  Coal  Tar  Colors. 

As  a  general  thing,  all  the  aniline  colors  are  very  little  solu- 
ble in  water;  the  blues  are  the  most  insoluble,  and  the  violets 
or  purples  next.  At  the  temperature  of  boiling  water, 
however,  the  reds  are  rendered  sufficiently  soluble  for  dyeing, 
and  the  more  so,  when  we  consider  that  the  bath  should  not 
contain  too  much  coloring  matter. 

The  true  solvents  of  these  dyes  are  alcohol,  methylic  alcohol 
or  wood  spirit,  acetone,  acetic  and  tartaric  acid,  sulphuric  acid, 
&c.  "Wood  spirit,  when  not  perfectly  pure,  will  turn  aniline 
reds  violet  or  blue;  this  is  probably  due  to  essential  oils  con- 
tained in  this  methylic  alcohol,  and  which  have  a  reducing 
action  similar  to  that  of  aldehyd. 

When  alcohol  is  used  as  a  solvent,  its  proportion  is  variable 
with  the  substance  it  has  to  dissolve. 

50  parts  of  alcohol  for  1  of  blue. 
30    "     "       "      "   1  of  violet, 

are  good  proportions.  The  iodine  blues  and  violet,  where  the 
iodine  has  been  left,  require  less  alcohol. 

The  solution  is  effected  in  copper  or  glazed  vessels,  which 
can  be  heated,  and  are  provided  with  condensing  worms,  in 
order  to  save  the  alcohol  which  distils  over.  The  solution  is 
allowed  to  stand,  filtered,  and  thrown  into  about  eight  times 
as  much  of  boiling  water,  to  which  some  tartaric  or  acetic  acid 
has  been  added.  For  economy's  sake,  sulphuric  acid  may  be 
used  instead  of  the  organic  acids,  which,  however,  are  to  be 
preferred,  if  very  fine  shades  are  required.  It  is  this  "  con- 
centrated solution"  which  will  be  made  use  of  for  gradually 
coloring  the  dye  bath. 

All  aniline  colors  precipitate  by  the  addition  of  a  solution 
of  tannin  (pure,  or  decoctions  of  sumac  or  of  gall  nuts).  The 
tannate  formed  is  soluble  in  alcohol,  acetic  acid,  or  diluted 
sulphuric  acid. 

They  are  also  insoluble  in  concentrated  solutions  of  alkaline 
salts,  such  as  chloride  of  sodium  (common  salt),  acetate  and 
sulphate  of  soda,  &c.  This  property  is  frequently  made  use  of 
for  recovering  the  color  from  old  baths,  or  purifying  these  dyes 
in  course  of  manufacture. 

The  expenses  resulting  from  the  employment  of  alcohol  for 
their  dissolution,  has  caused  several  methods  for  rendering  these 
colors  soluble  in  water.  Decoctions  of  certain  roots  have  been 
proposed,  and  have  not  been  very  successful. 

Concentrated  sulphuric  acid,  with  or  without  the  aid  of  heat, 
dissolves  the  aniline  blues  and  violets,  and  by  subsequent  re- 


DYEING  WITH  COAL  TAR  COLORS. 


389 


precipitation  of  the  color  by  the  addition  of  a  large  volume  of 
water,  it  is  rendered  sufficiently  soluble  in  hot  water.  This 
process  succeeds  better  with  the  blues  than  for  the  violets,  the 
shade  of  which  is  not  so  pure  as  before.  Even  for  the  blues, 
part  of  their  fastness  is  taken  off,  principally  when  the  solu- 
tion has  been  made  in  hot  sulphuric  acid. 

Soluble  Blues  or  Violets  are  those  colors  treated  by  sulphuric 
acid.  Too  much  solubility  would  be  a  defect  in  dyeing ;  all  that 
is  required  is  that  the  bath  should  dissolve  enough  of  the  color 
to  replace  that  taken  by  the  stuff,  and  that  the  color  should  not 
fall  to  the  bottom. 

It  is  at  present  rare,  to  find  impure  aniline  colors  in  the  trade; 
the  impurities  consist  generally  of  resinous  and  tarry  substances, 
formed  during  the  manufacture,  and  which  can  be  removed  by 
several  washings  with  coal  naphtha,  coal  oil,  and  other  hydro- 
carbons, which  do  not  dissolve  the  color. 

If  the  dye  is  soluble  in  boiling  water,  an  addition  of  fine  and 
sharp  sand  will  cause  the  impurities  to  stick  to  it.  Filtration 
terminates  the  operation. 

The  colors  derived  from  phenic  acid  and  naphthaline  are  often 
more  soluble  than  those  from  aniline. 

Eemarks  in  General  on  Dyeing  with  Coal  Tar  Colors. 

It  is  generally  more  easy  to  dye  with  coal  tar  colors,  than 
with  the  other  dyes  hitherto  used;  at  least,  as  regards  animal 
fibres.    Nevertheless  certain  precautions  are  necessary. 

The  animal  fibres,  wool  and  silk,  have  such  an  affinity  for  these 
colors,  that  they  will  immediately  deprive  a  bath  of  its  coloring 
matter,  and  be  unevenly  dyed.  This  points  to  a  constant  work- 
ing of  the  stuff  while  in  the  bath,  and  to  a  gradual  addition  of 
the  coloring  substance  to  the  vat.  The  more  soluble  the  color 
is,  the  more  these  conditions  should  be  attended  to. 

The  addition  of  some  acid,  generally  sulphuric,  tends  to  make 
the  color  more  soluble.  In  the  case  of  certain  blues  rendered 
too  soluble,  the  bath  should  not  contain  any  acid;  sometimes 
a  small  quantity  of  alkali  will  be  found  useful. 

The  degree  of  acidity,  and  the  temperature  of  the  bath,  have 
an  influence  on  the  shade.  Indeed,  many  shades  of  the  same 
color  are  produced  by  varying  the  temperature.  The  hotter 
and  the  more  acid  a  bath  is,  the  bluer  are  the  shades.  On  the 
other  hand,  a  bath  cold  and  with  little  acidity  gives  red  shades. 
Nevertheless,  the  goods  will  be  dyed  faster  if  the  temperature 
has  been  raised  near  the  boiling  point;  and  if  red  shades  are 
desired,  the  goods  are  allowed  to  rest  in  the  bath  until  it  has 
cooled  off. 


390 


DYEING  WITH  COAL  TAB  COLORS. 


The  temperature  for  dyeing  wool  is  generally  greater  than 
that  for  silk. 

The  color  being  dissolved,  as  we  have  explained  previously, 
is  gradually  added  to  the  bath,  the  temperature  of  which  is 
about  120°  Fah.  at  the  beginning  of  the  operation,  and  is  gra- 
dually raised  up  to  185°,  and  even  to  the  boiling  point.  In 
the  meantime  the  goods  are  worked  or  drawn  several  times,  in 
order  to  be  dyed  evenly. 

Vegetable  fibres,  except  in  the  case  of  emeraldine  green  or 
aniline  black,  are  without  affinity  for  aniline  colors.  On  that 
account  it  is  necessary  to  "animalize"  them,  that  is  to  say,  to 
impregnate  them  with  certain  organic  mordants,  which  will 
impart  to  them  the  property  of  attracting  and  fixing  these  dyes. 

The  mordants  employed  for  this  purpose  are  :  Albumen  from 
eggs  or  from  the  blood,  the  latter  only  for  dark  shades; 
lactarine  or  caseine  (curd  of  milk),  dissolved  in  caustic  soda  or 
acetic  acid;  gluten,  in  the  same  solvents;  gelatine,  and  tannate 
of  gelatine;  tannin  pure,  or  decoctions  of  sumach  or  gall  nuts; 
soap  and  the  transformed  oils,  as  for  Turkey  red ;  stannate  of 
soda  and  other  metallic  salts,  &c.  The  best  of  all,  if  it  were 
not  for  its  cost,  would  be  the  albumen  of  the  white  of  egg. 
The  color  attracted  and  fixed  by  this  substance,  becomes  fast 
on  the  fibre  by  the  coagulation  of  the  albumen  during  the 
steaming  process. 

If  gelatine  is  employed,  the  further  addition  of  tannin  will 
form  an  insoluble  compound,  which  will  retain  the  color  al- 
ready fixed  upon  the  fibre.  Tannin  and  metallic  salts  form,  also, 
insoluble  tannates. 

Steaming  makes  the  colors  more  fast,  and  is  also  a  test  of 
the  solidity  of  many  dyes.  At  the  beginning,  the  steam  is  let 
out  under  a  small  pressure,  which  is  afterwards  gradually  in- 
creased, but  is  never  very  high. 

Tannin  alone,  does  not  give  very  fast  colors;  the  fabric  had 
better  be  mordanted  previously  with  a  metallic  salt;  it  succeeds 
better  with  blues  than  with  magenta,  and  even  violets. 

For  instance,  a  good  process  for  dyeing  cotton  consists  in 
passing  the  cloth  through  a  decoction  of  sumac,  or  any  other 
substance  holding  tannin,  for  one  hour  or  two,  and  afterwards 
through  a  weak  solution  of  stannate  of  soda.  After  being 
worked  there  for  one  hour,  it  is  wrung  out,  and  dipped  into 
weak  sulphuric  acid  and  well  rinsed.  It  is  then  ready  to  be 
dyed  in  an  aniline  color  bath,  slightly  acidulated. 

For  calico  printing,  the  cotton  may  have  been  previously 
mordanted,  as  we  have  said,  and  then  printed,  steamed  and 
washed.  The  mordant  and  the  color  are  sometimes  printed  at 
the  same  time,  as  with  albumen  for  instance;  or  the  color  may 


COLORING  POWER  AND  NATURE  OF  ANILINE  COLORS.  391 


be  printed  first,  and  passed  through  the  mordanting  bath;  the 
first  process  seems  preferable.  • 

For  raising  the  shades,  a  passage  through  an  acidulated  liquor 
is  sometimes  resorted  to. 

The  discharges  are  made  by  means  of  powder  of  zinc,  which 
transforms  the  salts  of  rosaniline  into  white  leucaniline.  This 
substance  being  little  soluble,  the  washings  are  often  insuffi- 
cient to  remove  it  entirely,  and  what  remains  on  the  cloth  will 
be  oxidized  by  the  air,  and  transformed  again  into  colored 
salts  of  rosaniline.  By  the  use  of  the  permanganate  of  potassa 
or  lime,  on  the  contrary,  the  aniline  color  is  destroyed.  The 
permanganic  acid  is  set  at  liberty  by  sulphuric  acid,  which 
unites  with  its  base.  Inorganic  substances,  such  as  kaolin, 
freshly  precipitated  silica  and  alumina,  are  added  to  it,  in  order 
to  form  a  paste,  and  the  mixture  is  printed.  The  destroyed 
aniline  color  is  replaced  by  an  oxide  of  manganese,  which  is 
removed  by  washing  with  sulphurous  acid,  or  by  a  mixture  of 
hydrochloric  acid  and  protochloride  of  tin,  if  the  remaining 
color,  like  coralline,  is  acted  upon  by  the  sulphurous  acid. 

Many  more  colors,  and  processes  of  dyeing  and  calico  print- 
ing could  here  be  described ;  but  we  must  remain  within 
the  limits  of  this  work,  the  object  of  which  is  to  explain  the 
chemical  phenomena  of  the  art  of  dyeing,  rather  than  to  be  a 
book  of  receipts.  We  shall  finish  this  article  by  the  description 
of  a  simple  process  to  ascertain  the  coloring  power  and  the 
nature  of  aniline  colors,  which  we  borrow  from  M.  Riemann's 
book  on  aniline. 

Determination  of  the  Coloring  Power  and  Nature  of 
Aniline  Colors. 

Dissolve  10  grains  of  the  color  in  1  fluidounce  of  alcohol, 
in  a  vessel  heated  by  a  water  bath.  The  liquid  is  well 
shaken,  next  allowed  to  settle,  decanted  into  a  graduated 
tube,  and  what  remains  undissolved  treated  again  in  the 
same  manner  with  another  fluidounce  of  alcohol.  All  the 
color  being  dissolved,  a  tube  graduated  into  100  parts,  is 
filled  with  the  whole  of  the  alcoholic  solution,  plus  some  alco- 
hol to  fill  up  entirely  to  the  last  graduation.  The  tube,  there- 
fore, should  be  of  a  capacity  to  hold  at  least  the  quantity  of 
alcohol  used  for  the  solution. 

In  a  china  basin  a  sufficient  quantity  of  water  is  heated,  until 
it  is  too  hot  to  put  the  finger  in.  Then  20  grains  of  fleecy 
wool  are  weighed,  put  into  the  warm  water,  and  moved  about 
with  a  glajs  rod  until  the  wool  is  thoroughly  wetted.  It  is  then 


392 


IDENTIFICATION  OF  ANILINE  COLORS. 


taken  out,  and  4  divisions  of  the  colored  solution  are  added  and 
well  mixed.  The  wool  is  then*once  more  cautiously  immersed. 
It  will  now  be  dyed  by  the  solution,  and  when  all  the  color  is 
fixed,  a  fresh  portion  of  the  solution  is  added  to  the  bath,  until 
all  the  wool  is  dyed  of  the  desired  shade. 

The  value  of  the  coloring  matter  under  examination  is  in 
inverse  ratio  to  the  quantity  of  the  solution  consumed.  If  10 
divisions  of  the  standard  solution  a  were  necessary  to  dye  20 
grains  of  the  same  fleecy  wool  a  certain  shade,  and  14  divisions 
of  the  color  under  examination  b  produced  the  same  effect,  the 
proportion  is  14  :  10  ::  a  :  b.    Hence  b  is  f  of  a. 

Identification  of  Aniline  Colors. 

Aniline  colors  may  be  distinguished  from  one  another,  and 
for  this  purpose  Mr.  J.  J.  Pohl  uses  fuming  hydrochloric  acid, 
and  a  dilute  acid  consisting  of  one  part  strong  acid  to  three 
parts  of  water. 

The  effects  of  the  fuming  acid  are  observed  at  the  ordinary 
temperature  at  the  time  of  application,  after  5,  and  after  15 
minutes;  also  the  effect  of  dilution  is  then  observed.  Next, 
the  effects  of  the  dilute  acid  are  observed  at  first  and  after  15 
minutes.  Finally,  the  same  test  is  repeated  after  a  considerable 
dilution  with  water. 

The  following  table  shows  the  results  of  observations  made 
upon  the  several  aniline  colors: — 


IDENTIFICATION  OF  ANILINE 


COLORS. 


393 


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• 


APPENDIX. 


DYEING  AND  CALICO  PRINTING  AS  SHOWN  IN  THE  UNIVERSAL 
EXPOSITION,  PARIS,  1867. 


Extracts  from  the  Reports  of  the  International  Jury*  and  from 

other  Sources. 

It  is  well  known  that  silk,  by  the  process  of  dyeing,  can  have 
its  weight  increased  10  to  40  per  cent.,  and  yet  give  products 
of  a  good  quality.  The  competition  and  the  dearness  of  silk 
have  been  so  great  of  late  years,  that,  often,  the  weight  of  silk 
is  increased  150  to  200  per  cent,  by  dyeing,  especially  for 
blacks. 

Such  silk  is  rough  to  the  touch,  without  lustre,  easily  cut, 
and  will  not  last.  Heated  to  about  230°  Fah.,  it  will  fall  to 
pieces. 

By  this  process  of  over  adulteration,  silk  increases  much  in 
volume,  and  the  fibres,  viewed  under  the  microscope,  are 
swollen.  The  swelling  is  also  sensibly  in  proportion  with  the 
increase  of  weight. 

With  mordants  of  tannin,  tin,  and  oily  substances,  nearly  all 
the  new  coal-tar  colors  have  been  fixed  on  vegetable  fibres. 

Mr.  Eeimann,  of  Berlin,  dyes  cotton  yarn  with  aniline  colors, 
and  without  mordant,  by  effecting  the  operation  in  closed  ves- 
sel^ heated  up  to  about  300°  F.  The  shades,  on  leaving  the 
apparatus,  are  said  to  be  fast,  but  not  bright.  They  are  raised 
by  another  dyeing  operation  conducted  in  the  open  air. 

Such  a  process  requires  costly  apparatus,  does  not  allow  an 
easy  dyeing  to  a  given  shade,  and,  granting  that  the  dyed 
ground  is  fast,  it  does  not  appear  that  the  raising  given  after- 
wards will  be  faster  than  by  the  ordinary  process.  Neverthe- 

*  Rapports  du  Jury  International,  publies  sous  la  direction  de  M.  Michel 
Chevalier,  Membre  de  la  Commission  Imperiale.    13  vols.  8vo.  Paris,  1868. 


396 


APPENDIX. 


less,  the  application  of  dyeing  under  pressure  in  closed  vessels, 
is  a  curious  one,  and  might  be  used  to  advantage  in  other  cases. 

Since  Messrs.  Tessie  du  Motay  and  Mardchal  have  succeeded 
in  producing  cheaply  alkaline  permanganates,  these  salts  begin 
to  be  used  for  bleaching  goods.  By  the  decomposition  of  the 
permanganate,  its  oxygen  destroys  or  modifies  the  substances 
foreign  to  the  cloth,  which  are  washed  out.  At  the  same  time, 
oxide  of  manganese  is  precipitated  upon  the  cloth,  and  is  re- 
moved by  washing  in  a  dilute  sulphurous  acid  solution.  The 
solution  of  permanganate  of  soda  is  also  to  be  employed  in 
a  dilute  state. 

Feathers  may  be  bleached  by  the  process  of  Messrs.  Viol  and 
Duflot,  as  follows :  Steep  the  feathers  for  from  three  to  four 
hours  in  a  tepid  and  diluted  bath  of  bichromate  of  potassa  with 
nitric  acid,  then  pass  through  another  bath  holding  a  very  weak 
solution  of  sulphurous  acid,  and  rinse. 

Dyeing  aniline  black  on  wool  has  not  been  entirely  success- 
ful, notwithstanding  the  chlorine  process  of  Mr.  Lightfoot. 
Some  recent  experiments,  however,  permit  us  to  hope  that  ani- 
line black  will  be  employed  for  wool  as  well  as  for  cotton. 

Casein  (curd  of  milk),  as  a  mordant,  is  better  dissolved  in 
crystallizable  acetic  acid,  or  in  a  milk  of  lime.  In  the  latter 
case,  the  colors  are  said  to  be  faster  than  when  using  casein 
dissolved  in  ammonia  water,  or  even  than  with  albumen. 
But  printing  should  be  effected  rapidly,  because  the  paste 
loses  its  fluidity  very  rapidly,  especially  with  ultramarine. 

By  means  of  a  metallic  engraving  in  relief,  which  distributes 
drops  of  colored  and  melted  resin  on  silk  goods,  Mr.  Petitdidier 
imitates  embroideries  and  tapestry  work. 

Light  tissues,  like  tulle  or  bobbinets,  are  also  covered  with 
drops  of  gelatin,  or  gum,  which  fall  from  rows  of  pins,  variously 
arranged,  according  to  the  processes  of  Messrs.  C.  Depouilly, 
Meyer,  and  Agnelet  brothers. 

By  printing,  in  a  peculiar  way,  silk  warps  previous  to  weav- 
ing, various  combinations  of  figures  and  designs  may  be  effected 
on  the  loom,  without  the  expense  of  the  cartoons  of  the 
Jacquart  loom. 

The  various  aniline  blacks,  prepared  whether  by  the  bichro- 
mate of  potassa,  or  by  the  chlorate,  are  soluble  in  a  mixture  of 


APPENDIX. 


397 


alcohol  and  sulphuric  a6id.  This  solution,  thrown  into  a  large 
quantity  of  water,  dyes  animal  fibres  a  fast  gray. 

For  dyeing  black  on  cotton,  Messrs.  Paraf  and  Javal,  pass  the 
cloth  through  a  bath  containing  a  mixture  of  sulphate  of  ani- 
line and  bichromate  of  potassa.  The  color  appears  on  the 
fabric  immediately  after  it  leaves  the  bath,  the  temperature  of 
which  must  be  kept  a  little  below  the  freezing  point,  not  above. 

Another  method  consists  in  mordanting  the  cotton  cloth 
with  chromate  of  lead,  and  then  passing  it  through  an  acidu- 
lated bath  of  oxalate  of  aniline.  In  this  case,  the  reaction 
taking  place  only  on  the  cloth,  the  temperature  has  not  to  be 
so  strictly  low  as  in  the  former  method. 

Mr.  Dumas  frees  indigo  from  its  red  and  brown  coloring 
substances  by  aniline.  Indigo  thus  purified  gives  very  good 
results  when  used  in  printing  on  cotton. 

One  of  our  cotemporaries  speaks  of  chloroform  as  being  a 
solvent  of  indigo.  Not  having  tried  the  process,  we  can  but 
believe  that  the  chloroform  may  be  a  solvent  of  the  impurities 
of  indigo,  rather  than  of  indigo  itself. 

From  the  same  source  we  find  for  dyeing  animal  fibres  a 
silver  gray  color  :  Boil  10  pounds  of  wool  in  a  bath  containing 
4  ozs.  of  sulphuric  acid,  and  4  ozs.  of  glauber  salts  (sulphate  of 
soda).  Then  dye  to  the  shade  by  means  of  iodine  violet  and 
some  carmine  of  indigo. 

There  are  many  recipes  for  the  preparation  of  the  printing 
paste  for  aniline  black  ;  they  can  be  summed  up  into  a  com- 
position of  tartrate  of  aniline,  sulphide  of  copper,  chlorate  of 
potassa,  and  sal-ammoniac,  the  whole  thickened  with  a  mix- 
ture of  starch  and  torrefied  starch,  with  enough  water  to  make 
the  volume  of  the  aniline  about  one-tenth  of  the  whole. 

Aniline  black  succeeds  very  well  when  printed  with  or  under 
chrome  orange.    In  this  case  the  lead  mordant  is  basic. 

Mr.  Horace  Koechlin  has  succeeded  in  printing  aniline  greens 
on  silk  and  wool  by  adding  alkaline  sulphites  to  the  color. 

For  cotton  goods,  besides  the  sulphite,  some  tannin  is  neces- 
sary. 

The  following  are  the  values  in  coloring  power  of  several 
madder  extracts: — 

That  of  Professor  Eochleder,  of  Prague,  is  dry  and  equal  to 
140  times  its  weight  of  madder ;  that  of  Messrs.  Pernod  and 
Picard,  of  Avignon,  is  in  paste  and  equal  to  16  to  20  times  its 


398 


APPENDIX. 


weight  of  madder;  that  of  Mr.  Schutzenberger,  manufactured 
by  Mr.  C.  Meissonnier,  is  also  in  paste  and  equal  to  30  times 
its  weight  of  madder. 

These  extracts  are  free  from  resinous  matters,  and  therefore 
can  be  thoroughly  mixed  with  water,  but  they  require  a  nice 
adjustment  in  the  proportion  of  mordants.  The  steaming  pro- 
cess lasts  two  or  three  times  as  long  as  with  ordinary  steam 
colors.  The  shades  are  also  to  be  raised  by  drawing  the 
printed  goods  through  soap  baths.  No  mixture  of  acids, 
oxidizing  agents,  or  ageing  is  necessary.  The  principal  mor- 
dants still  used  are  those  of  alumina  and  iron. 

On  the  other  hand,  some  persons  assert  that  it  is  possible  to 
print  with  these  extracts,  on  tissues  which  have  not  been  mor- 
danted. 

Rosin  soap,  for  bleaching  cotton  goods,  has  been  used  for 
several  years,  instead  of  ordinary  soaps.  Besides  its  cheap- 
ness, the  action  of  this  soap  is  more  effective,  removing  entirely 
the  resinous  substances  of  the  cotton  goods,  probably  in  accord- 
ance with  the  rule  that  "like  dissolves  like."  Soda  ash  is  also 
used  in  connection  with  rosin  soap,  and  its  action  is  facilitated 
when  the  goods  have  been  previously  submitted  to  the  liming 
process.  Rosin  soap,  combining  with  the  soap  made  by  the 
alkali  and  the  fatty  matters  on  the  goods,  prevents  the  decom- 
position of  the  latter  soap,  which  often  takes  place  in  presence 
of  saline  matters,  and  produces  blotches  on  the  bleached  goods. 

One  of  the  main  improvements  in  bleaching  calicoes,  has 
been  that  of  effecting  the  operation  under  high  pressure,  by 
forcing  the  scouring  liquor  to  circulate  through  the  cloth. 

Another  improvement  consists  in  transforming  the  starch, 
which  enters  into  the  composition  of  sizing  for  the  warps,  into 
dextrine  or  sugar,  easily  removed.  For  this  purpose,  the 
pieces  are  soaked  in  water  at  the  temperature  of  140°,  to 
which  a  small  quantity  of  malt  is  added,  and  causes  the  above- 
named  transformation. 


GLOSSARY  OF  TECHNICAL  TERMS 

USED  IN  THE  DYE-HOUSE, 

WITH  THE  CHEMICAL  NAMES  : 

A  FULL  EXPLANATION  OF  WHICH  MAY  BE  OBTAINED  IN  THE  VOLUME. 


Adjective.  A  term  applied  to  a  color  depending  on  a  base  for  its  pro- 
duction. 
Aqua-fortis.  Nitric  acid. 

Aqua-regia.  A  mixture  of  hydrochloric  and  nitric  acids,  generally  In 

the  proportion  of  2  of  the  former  to  1  of  the  latter. 
Alkali  root.  Alkanet  root. 

Alterant.  A  substance  added  to  a  color  to  give  it  brightness,  same  as 
"  raising." 

Argol.  Bitartrate  of  potash,  formed  by  deposit  in  wine  casks. 
Am  otto.  Annotta. 

Barilla.  The  name  of  an  impure  soda  imported  from  Spain  and  the 
Levant. 

Black  ash.  Carbonate  of  potash  in  fused  masses,  as  imported. 
Black  lead.  Carburet  of  iron,  Plumbago. 
Black  iron  liquor.  Acetate  of  iron,  or  pyrolignite  of  iron. 
Bleed.  To  extract  the  coloring  matter  from  a  dye  drug. 
Bleaching  'powder.  Chloride  of  lime. 

Block  tin.  Commercial  tin  cast  into  ingots  or  blocks,  not  so  pure  as 

grain  tin. 
Borax.  Borate  of  soda. 
Blue  copperas.  Sulphate  of  copper. 
Blue-stone.  Sulphate  of  copper. 
Blue  vitriol.  Sulphate  of  copper. 

Bottom.  Applied  to  the  base  of  a  color  such  as  sumach,  galls,  &c. 
Brimstone.  Sulphur. 

Brown  sugar.  Acetate  of  lead,  or  pyrolignite  of  lead. 
Bucking.  Boiling  goods  in  alkalies,  sometimes  Bowking. 
Bundle.  Ten  pounds  of  cotton  yarn. 
Calomel.  Protochloride  of  mercury. 

Carmine.  Coloring  matter  of  cochineal,  extracted  and  dried. 
Chamber  lye.  Urine. 

ChemiCj  or  chemic  blue.  Sulphate  of  indigo. 
Chrome.  Bichromate  of  potash. 


400 


GLOSSARY. 


Common  salt.  Chloride  of  sodium. 
Copperas,  Protosulphate  of  iron. 

Corrosive  sublimate.  Bichloride  of  mercury.  • 
Cream  of  tartar.  Bitartrate  of  potash,  purified.    See  argol. 
Crofting.  Exposing  goods  upon  the  grass  for  bleaching. 
Crude  tartar.  See  argol. 

Dip.  Generally  applied  to  immersing  goods  in  the  blue  vat. 
Doctored.  To  adulterate,  generally  applied  to  giving  an  appearance 

of  strong  color  to  dyewoods,  by  adding  water  to  them. 
Double  muriate  of  tin.  Bichloride  of  tin. 
Epsom  salts.  Sulphate  of  magnesia. 
Essential  salt  of  lemons.  Binoxalate  of  potash. 
Extract  of  Indigo.  Sulphate  of  indigo. 
Fast  Color.  Permanent  color. 
Fancy  Color.  Colors  subject  to  fade,  fugitive. 
Feathering.  To  granulate  a  metal. 

Firing  spirits.  When  tin  by  dissolving  too  rapidly  or  by  heat,  be- 
comes converted  into  a  bichloride. 

Fluery  of  a  vat.  The  froth  of  oxidized  indigo  floating  on  the  surface 
of  a  blue  vat. 

Flowers  of  zinc.  Oxide  of  zinc. 

French  tub.  Protochloride  of  tin  and  logwood,  plump  tub. 

Glauber  salts.  Sulphate  of  soda. 

Grain  tin.  Metallic  tin  in  prismatic  pieces. 

Green  vitriol.  Sulphate  of  iron,  copperas. 

Hartshorn.  Ammonia. 

Kelp.  Ashes  left  on  burning  sea-weed. 

Killing.  Dissolving  any  substance  in  an  acid,  as  iron  in  nitric  acid, 

killing  iron. 
King's  yellow.  Sulphuret  of  arsenic. 

Lactine.  A  curd  of  milk  used  for  annualizing  cotton,  lactarine. 

Lemon  juice.  Citric  acid. 

Lye.  Solution  of  an  alkali,  as  potash  or  soda. 

Lime  shell.  Caustic  lime. 

Limestone.  Carbonate  of  lime. 

Litharge.  Protoxide  of  lead. 

Lunar  caustic.  Nitrate  of  silver. 

Magnesia  nigra.  Manganese. 

Marine  acid.  Hydrochloric  acid. 

Mineral  alkali.  Soda. 

Mordant.  Generally  applied  only  to  acetate  of  alumina. 
Muriatic  acid.  Hydrochloric  acid. 
Muriates.  Chlorides. 

Nitromuriate  of  tin.  A  solution  of  tin  in  nitric  and  hydrochloric 

acids,  forming  a  persalt. 
Nitre.  Nitrate  of  potash. 
Oxymuriate  of  tin.  Perchloride  of  tin. 
Oxymuriate  of  potash.  Chlorate  of  potash. 
Oxymuriatic  acid.  Chlorine. 
Oil  of  vitriol.  Sulphuric  acid 


GLOSSARY. 


401 


Orpiment.  Sulphuret  of  arsenic. 

Oxygen  of  the  bleachers.  Chlorine,  chloride  of  lime,  bleaching  pow- 
der. 

Pearlash.  Carbonate  of  potash. 

Permuriate  of  tin.  Perchloride  of  tin. 

Prussiate  of  potash.  Ferrocyanide  of  potassium. 

Queen-wood.  Brazil-wood. 

Quicksilver.  Mercury. 

Raising.  See  alterant. 

Realgar.  Sulphuret  of  arsenic. 

Red  chrome.  Bichromate  of  potash. 

Red  liquor.  Acetate  of  alumina. 

Rot  steep.  Steeping  cloth  in  old  lyes  to  soften  the  paste;  fermenta- 
tion takes  place,  hence  the  name. 
Roman  vitriol.  Sulphate  of  copper. 

Saddening.  Making  a  color  darker  by  means  of  a  salt  of  iron. 
Sal  ammoniac.  Chloride  of  ammonium. 
Sali  nixon.  Bisulphate  of  potash. 

Sal  prunella.  Fused  nitrate  of  potash  cast  into  balls,  or  cakes. 

Sal  volatile.  Sesquicarbonate  of  ammonia. 

Salt  of  lemons.  Citric  acid. 

Salt  of  saturn.  Acetate  of  lead. 

Salt  of  soda.  Carbonate  of  soda. 

Salt  of  sorrel.  Binoxalate  of  potash. 

Salt  of  tartar.  Carbonate  of  potash. 

Salt  of  vitriol.  Sulphate  of  zinc. 

Salt  perlate.  Phosphate  of  soda. 

Saltpetre.  Nitrate  of  potash. 

Salt  sedative.  Boracic  acid. 

Salts  of  tin.  Crystallized  protochloride  of  tin. 

Salt  cake.  Sulphate  of  soda. 

Saxon  blue.  Sulphate  of  indigo. 

Scalding.  Extracting  a  coloring  matter  by  boiling  water. 

Smalt  blue.  Ground  glass,  made  of  alumina,  silica,  potash,  or  soda, 

colored  blue  by  oxide  of  cobalt. 
Slaked  lime.  Hydrate  of  lime. 
Sludge.  Sediment  of  the  blue  vat. 
Single  muriate  of  tin.  Protochloride  of  tin. 
Sour.  Water  made  acid  by  sulphuric  acid. 
Soda  ash.  Carbonate  of  soda. 
Spirits.  Solutions  of  chlorides  of  tin. 
Spirits  of  salt.  Hydrochloric  acid. 
Spirits  of  hartshorn.  Ammonia. 
Spirits  of  wine.  Alcohol. 
Spent.  Exhausted  of  color. 
Stoveing.  Hanging  goods  in  the  stove  to  dry. 

Stock  tab.  Vessel  filled  with  strong  solution  of  a  substance  to  be  kept 
for  use. 

Sugar  of  lead.  Acetate  of  lead. 
26 


402 


GLOSSARY. 


Substantive  color.  A  color  fixed  in  the  fibre  without  base  or  com- 
pound. 

Supertartrate  of  potash.   See  argol. 

Sweeten.  To  pour  water  upon  goods,  from  a  sour,  as  a  partial  wash. 

Tartar.  See  argol. 

Test  blue.  Sulphate  of  indigo. 

Tincal.  Borate  of  soda,  borax. 

TumbulVs  blue.  Ferrocyanide  of  iron,  Prussian  blue. 

Vegetable  alkali.  Potash. 

Verdigris.  Acetate  of  copper. 

Verditer.  Acetate  of  copper. 

Vinegar.  Acetic  acid. 

Vitriol.  Sulphuric  acid. 

Volatile  alkali.  Ammonia. 

White  vitriol.  Sulphate  of  zinc. 

White  copperas.  Sulphate  of  zinc. 

White  lead.  Carbonate  of  lead. 

Whiting  Carbonate  of  lime. 

White  zinc,  Oxide  of  zinc. 


ERRATA. 


On  Page  386,  twentieth  line  from  top,  for  'picric  read  phenic. 
On  Page  46,  fourth  line  from  top,  for  cynogen  read  cyanogen. 


I 


INDEX. 


Abstracting  tannin  from  galls,  242 

Acacia  catechu,  254 

Acetate  of  alumina,  141,  227 

of  barytes,  135 

of  copper,  169,  228 

of  iron,  157 

of  iron  and  alumina,  227 

of  lead,  171 

of  tin,  183 
Acetic  acid  combines  with  copper,  169 

acid,  composition  of,  236 
Acid,  anilic,  279,  282 

antimonic,  199,  200 

binitro-naphthylic,  387 

boracic,  106 

bromic,  105 

carboazotic,  386 

carbazotic,  280 

carbolic,  375 

carbonic,  108 

chloric,  70 

chloroxynaphthalic,  387 

chromic,  185 

citric,  for  printing,  146 

colors  from  carbolic  or  phenic,  385 

compounds,  236 

ferro-prussic,  119 

fluosilicic,  105 

gallic,  242 

gallic,  small  quantity  in  vegetables, 
243 

hydrobromic,  105 
hydrofluoric,  105 
hydriodic,  104 
hydrochloric,  70 
hydrocyanic,  110 
hypochloric,  69 
hypochlorous,  69 
hyposulphuric,  101 
hyposulphurous,  100 
indigotic,  279,  282 
isatinic,  280,  282 
isopurpuric,  386 
iodic,  104 
luteo-gallic,  249 
molybdic,  195 


Acid — 

muriatic,  70 
nitric,  61 
nitrous,  61 
oxalic,  109 
oxymuriatic,  68 
picric,  280,  386 
pyroligneous,  144 
silicic,  106 
stannic,  180 
sulphindylic,  283 
sulpho- purpuric,  283 
sulphuric,  95 
sulphurous,  94 
tannic,  242 
telluric,  196 
tellurous,  196 
trinitrophenic,  386 
tungstic,  194 
valerianic,  279,  282 
vanadic,  193 
uric,  dye  from,  372 
yellow,  190 

action  on  Brazil  wood,  316 
Acids,  effect  on  catechu,  255 

of  arsenic,  197 

of  coal-tar,  374 

of  phosphorus,  103 

prevent  fermentation  in  galls,  246 

madder,  339 
Acorns,  cups  of,  258 
Act  against  use  of  logwood,  306 
Actino-chemistry,  28 
Action  of  agents  upon  annotta,  350 

of  alumina  salts  on  others,  148 

of  bases  upon  colors,  218 

of  catechu  in  dyeing,  256 

of  chemicals  on  hematoxylin,  308 

of  chemicals  on  indigo,  277 

of  metallic  salts  on  galls  or  su- 
mach, 246 

of  light  on  nitric  acid,  63 

of  mordants,  228 
Adjective  colors,  220 
Adulteration  in  indigo,  273 

of  catechu,  25b" 


404 


INDEX. 


Adulteration — 

of  cochineal,  369 

of  litharge,  170 

of  silk,  395 
Adulterations  in  indigo  extract,  286 

of  annotta,  351 

of  soap,  132 

of  madder,  336,  346 
Affinity,  41 

elective,  in  dyeing,  324 

for  coal-tar  colors,  389 

for  dyes,  214 

of  cochineal,  369 
Africa,  iudigoes  from,  276 
Agates,  106 
Agnelet  process,  396 
Air,  oxygen  in,  47 
Albumen  as  a  mordant,  390 
Alcohol  as  a  solvent  for  aniline,  388 

composition  of,  236 

with  barwood,  318 
Aldehyd  green,  383 
Algaroba  liquor,  359 
Alizarin,  337 

attraction  of  phosphates  for,  338 

extraction  of,  337 

naphthaline  of,  387 

reaction  of,  337 
Alizarine,  345  • 

impure,  343 
Alkalies,  action  on  Brazil  wood,  316 

action  on  indigo,  277 

contain  nitrogen,  236 

effect  on  catechu,  255 
Alkalimeter,  82 
Alkaline  earths,  137 

permanganates,  396 

salts  of  lead  for  dyeing,  173 

sulphites  for  printing,  397 
Alkaloids  of  coal-tar,  374 
Alkanet,  reactions  of,  352 

root,  352 
Alloy  with  zinc,  164 
Alloys,  112 
Alloxane,  372 

action  on  fibres,  213 
Aloes,  363 

as  a  dye,  363 

patent  for  preparing,  363 
Alsace  madder,  335 
Alterants,  217 
Alum,  137 

as  a  mordant,  228 

cake,  141 

best  mordant  for  Brazil  wood,  317 
mordants,  145 
ore,  138 
shale,  138 
stone,  138 
Alumina,  137,  148 


Alumina — 

acetate  of,  141,  227 
detected  in  copperas,  156 
detection  of,  148 
mordant,  215 

mordants  with  cochineal,  369 

salts  of,  148 

subacetate  of,  147 
Aluminous  lake,  354 
Aluminate  of  soda,  141 
Amalgam  of  gold,  205 

of  silver,  203 
Amber  from  acetate  of  lead,  172 

from  chrome,  190 
America,  indigoes  from,  276 
Ammonia,  67 

alum,  139 

chloroxynaphthalate  of,  387 

in  atmosphere,  62 

isopurpurate  of,  386 

purpurate  of,  371 
Analogies  of  blues,  309 
Analysis  of  catechu,  255,  256,  258 

of  cochineal,  366 

of  flax,  211 

of  morindine,  356 

of  Neapolitan  silk,  222 
Anderson  on  sooranjee,  355 
Anil,  375 

Anilic  acid,  279,  282 
Aniline,  375 

black  on  wool,  396 

black,  printing  paste  for  397 

blacks,  solvent  for,  396 

blacks  and  grays,  384 

blue,  379 

blues  and  violets,  381 
brown,  387 

browns  and  maroons,  385 
colors,  373 

colors,  coloring  power  and  nature 
of,  391 

colors,  identification  of,  392 
colors,  determination  of,  391 
colors,  Pohl's  method  of  identify- 
ing, 392 
colors,  steaming,  390 
colors,  value  of,  391 
green  printing,  397 
greens,  383 

greens,  Koechlin  on,  397 
orange,  382 
reds,  380 

to  purify  indigo,  397 
violet,  379 
yellows,  382 
Animal  charcoal  in  dyeing,  230 
fibres,  gray  for,  397 
fibres,  affinity  for  coal-tar  colors, 
389 


INDEX. 


405 


Animal — 

matters  used  in  dyeing,  365 
Animals,  oxygen  in,  47 
Animalization,  390 
Animalizing  cotton,  222 
Annotta,  348 

adulterations  of,  351 

Carribee's  preparation  of,  349 

colors  from,  350 

extraction  of,  349 

ingredients  of,  349 

John's  examination  of,  349 

nankeen  dye  from,  351 

reaction  with,  350,  351 

tests  for,  351 

to  color  butter  and  cheese,  351 
Anthon's  method  of  valuing  cochineal, 
367 

Antidote  for  arsenic,  197 
Antimonic  acid,  199 
Antimony,  199 

Antoine's  experiments  with  galls,  244 

Anyle,  278 

Appendix,  395 

Application  of  affinity,  42 

Aqua  regia,  130 

Archil,  352 

effect  of  lime  upon,  224 

mordants  not  required  for,  353 

preparing,  352 

reaction  with,  353 

reds  from,  353 
Army  cloth,  how  dyed,  301 
Arnotto,  348 

Arrangement  of  colors,  31 
Arseniate,  and  arsenite  of  copper,  169 
Arsenic,  196 
Arsenic  acicl,  197,  198 

sages,  197 
Ash,  113 

Asia,  indigoes  from,  275 
Astringents  important  in  dyeing,  221 
Astringent  nature  of  plants,  241 
Attraction  between  fibre  and  coloring 

matter,  332 
Autumn,  cause  of  change  in  plants,  239 
Avignon  madder,  335 
Azaleine,  380 
Azote,  59 
Azuline,  386 
Azurine,  383 

Bachelier  uses  lime  and  casein,  223 
Ball-soda,  124 
Bancroft  on  lac,  370 

on  aloes  as  a  dye,  363 
Bancroft's  arrangement  of  colors,  220 

use  of  quercitron,  323 
Bansdorff's  theory  for  varieties  of 
copperas,  154 


Barbary  root,  364 
Solly  on,  364 
Barium,  134 
Bark,  323  * 
Barks  for  dyeing,  258 
Barreswil  on  reaction  of  iron  and  tan- 
nin, 251 
Barwood,  317 

spirits,  183,  225 
Barytes,  134 
Bases,  112 

action  upon  colors,  218 

as  mordants,  215 

contain  nitrogen,  236 

from  aniline,  378 
Basic  salts  of  lead,  171,  172 
Bath  for  dyeing  cotton  on  silk,  384 
Bechamp  on  making  aniline,  376 
Beeswax,  composition  of,  236 
Bengal  catechu,  255 

indigoes,  275 
Benzole,  375 

Berthollet  on  greens,  237 

on  indigo  fermentation,  263 
on  tin  as  a  mordant,  176 

Berthollet's  experiments,  77 

Berzelius  on  impurities  in  indigo,  266 
on  reaction  of  iron  and  tannin,  251 
process  of  selecting  indigo,  266 

Bichloride  of  platinum,  207 

of  tin,  action  on  fibres,  213 

Bichlorisatin,  281,  282 

Bichromate  of  potash,  188 

of  potash,  action  of  light  on,  30 
of  potash,  as  a  mordant,  228 
of  potash,  in  dyeing,  282 
of  potash,  tests  for,  193 

Bignonia  chica,  359 

Binitro-naphthylic  acid,  387 

Binoxalate  of  potash,  118 

Binoxide  of  hydrogen,  58 
of  nitrogen,  60 
of  tungsten,  194 

Biphosphate  of  potash,  118 

"Birmingham,  sulphate  of  copper  pro- 
duced in,  168 

Bismuth,  174 

Bisulphate  of  iron,  155 
of  potash,  117 

Bisulphuret  of  iron,  154 

Bisulphuretted  hydrogen,  102 

Bitartrate  of  potash  as  a  mordant,  228 

Bixa  orellana,  348 

Bixeine,  351 

Bixine,  351 

Blacks,  aniline,  on  wool,  396 
Black  ash,  114 
Blacks,  aniline,  384 
Black,  best  dyed  with  pyrolignite  of 
iron,  157 


406 


INDEX. 


Black- 
dyeing  with  sumach,  250 
flux,  113 

from  naphthaline,  387 
from  fustic,  322 
iron  liquor,  227 
jack,  164 
lead,  107 

printing  paste  for  aniline,  397 

soap,  132 

tannin  superior  for  dyeing,  246 
Blauholz,  306 
Bleaching,  75 

calicoes,  improvement  in,  398 

cotton  goods,  398 

liquor,  80 

of  feathers,  396 

powder,  80 

powder  to  make  peroxide  of  lead, 
171 

powder,  value  of,  81 

with  cobalt,  163 

with  sulphurous  acid,  94 
Blende,  164 
Bleu  de  nuit,  381 

lumiere,  382 
Block  tin,  176 
Blue,  analogies  of,  309 

china,  283 

color  from  alumina,  148 

coloring  matters,  composition  of, 

309 

crust  on  lead,  170  * 
dyeing,  121 

dyeing  silks  and  woollens,  286 

for  porcelain  and  glass,  162 

from  red  flowers,  240 

ground,  white  pattern  on,  282 

iron  and  tin  for,  227 

Prussian,  from  nitrate  of  iron,  159 
Blues,  aniline,  381 

from  naphthaline,  387 

indigo,  composition  of,  309 

mordant  for,  228 

soluble,  389 
Blue-stone,  168 

sages,  169 
Blue  vat,  how  made,  288 

vitriol,  168 
Boiling  lye,  85 

of  liquids,  21 
Bois  bleu,  306 

de  campeche,  306 

de  pernambouc,  314 
Bolley's  method  of  testing  indigo,  273 
Bolley  on  quercitron,  324 
Bombay  catechu,  255 
Bombix,  212 

Bones  colored  by  madder,  338 
Boracic  acid,  106 


Borate  of  soda,  106,  130, 
Borax,  106 
Boron,  106 

Bottom,  definition  of,  250 
Braconnot  on  casein,  223 
Brasileto,  314 
Brass,  112,  164 

Brazil  dye,  action  of  metals  on,  316 

Brazil,  indigoes  of,  276 

wood,  action  of  acids  on,  316 
wood,  action  of  alkalies  on,  316 
woods,  314 

Brazilienholz,  314 

Brezilin,  315 

Brezilein,  316 

Brezilin,  composition  of,  316 
British  barilla,  124 
Bromates,  105 
Bromic  acid,  105 
Bromine,  105 
Brown,  aniline,  387 

from  manganese,  150 
Browning,  225 
Brown,  Jacobsen's,  387. 

madder,  339 

maroon,  de  Laire's,  385 

picric  acid,  387 
Browns,  aniline,  385 
Brown  sugar  of  dyers,  172 

upon  yarns  from  bark,  324 
Broquette  uses  casein  as  a  mordant, 

222 
Bucking,  76 

Buff,  from  nitrate  of  iron,  159 
Butter  colored  with  annotta,  351 

Cabbage  affected  by  light,  238 
Cadmium,  166 
Cxsalpina  brasileta,  314 

cresta,  314 
Calamine,  164 

Calcareous  waters  for  madder,  348 
Calcium,  135 

Calico  printing  with  coal-tar  colors,  390 
Calorific  rays,  25 
Calvert's  green,  383 
Campeachy  wood,  306 
Camwood,  320 
Cannabis  saliva,  212 
Caoutchouc,  composition  of,  236 
Carbazotic  acid,  280 
Caraccas  indigoes,  276 
Carajuru,  358 
Carboazotic  acid,  386 
Carbolic  acid,  375 
acid  colors,  385 

or  phenic  acid,  colors  from,  385 
Carbon,  106 
Carbonated  alkali,  114 
Carburetted  hydrogen,  111 


INDEX. 


407 


Carbonate  of  iron,  157 

of  lead,  171 

of  lime,  136 

of  nickel,  164 

of  soda,  124 
Carbonates  of  lime,  135 
Carbonic  acid,  108 

decomposed  by  light,  29 

oxide,  108 
Carmine,  366,  369 

of  indigo,  305 

reaction  with,  366 
Carolina  indigoes,  276 
Carribees'  preparation  of  annotta,  349 
Carthamus,  329 
Carthamine,  329 
Carucuru,  359 

Carves  and  Thirault,  mureine  grays,  38 

Caseate  of  lime,  223 

Casein  as  a  mordant,  222,  396 

Castelhaz's  mauveine  gray,  385 

Catalysis,  43 

Catalytic  influence,  43 

Catechu,  254 

action  in  dyeing.  256 

adulteration  of.  256 

impurities  in,  256 

Malabar,  256 

reactions  of,  257 

spurious,  256 
Caustic  lime,  135 

potash,  116 

potassa,  action  on  fibres,  213 

soda,  124 
Celery  affected  by  light,  238 
Cerium,  201 
Cerulin,  283 

Chalk  necessary  sometimes  in  water 
248 

Chameleon,  mineral,  150 
Change  in  hues  in  leaves,  239 
Characteristics  of  indigo,  277 
Charcoal,  107 
Charcoal  in  dyeing,  230 
Cheese  colored  with  annotta,  351 
Chemic,  80,  283,  285 
Chemical  affinity,  41 

changes  in  making  indigo,  263 
composition  of  indigo,  277 
effects  of  heat  upon  colors,  23 
investigation  of  logwood,  309 
names,  399 
nomenclature,  37 
rays,  25 

Chemistry  necessary  in  dyeing,  216, 
248 

Chevalier,  reports  on  exposition,  395 
Chevreul  on  fustic,  321 

on  indigoes,  274 

on  quercitron,  324 


Chevreul — 

on  reaction  of  iron  and  tannin,  251 
Chevreul's  analysis  of  pastel,  294 

examination  of  logwood,  306 

experiments,  232 

process  for  Brazil  wood,  315 

process  of  selecting  indigo,  266 

process  to  obtain  coloring  matter 
from  logwood,  307 
Chica,  358 
China,  blue,  283 
Chlorate  of  potash,  118 
Chloric  acid,  70 
Chloride  of  antimony,  199 

of  barium,  134 

of  cadmium,  166 

of  calcium,  136 

of  chromium,  186 

of  copper,  168 

of  gold,  206 

of  iron,  157 

of  lead,  173 

of  lime,  80 

of  manganese,  150 

of  nickel,  164 

of  nitrogen,  74 

of  palladium,  208 

of  platinum,  207 

of  silver,  203 

of  silver,  effect  of  light  on,  29 
of  sodium,  124,  130 
of  strontium,  135 
of  tin,  177 

of  tin  as  a  mordant,  228 

of  zinc,  165 
Chlorides,  71 

of  iridium,  209 

of  osmium,  209 
Chlorimeter,  87 
Chlorimetry,  86 
Chlorindoptin,  281,  282 
Chlorine,  68 

acting  on  indigo,  281 

bleaching,  78 

effect  of  light  on,  28 

process,  Lightfoot's,  396 
Chlorisatin,  281,  282 
Chloroform  as  a  solvent  of  indigo,  397 
Chloronile,  281,  282 
Chlorophyllite,  237 
Chloroxynaphthalate  of  ammonia,  387 
Chloroxynaphthalic  acid,  387 
Chocolate  from  morindine,  357 
Choice  of  mordants,  215 
Chromate  of  copper,  action  of  light  on, 
30 

of  lead,  189 

of  lead  as  a  mordant,  397 
Chromates  of  potash,  187 
Chrome  as  a  mordant,  192 


408 


INDEX. 


Chrome — 

colors  affected  by  light,  30 

green,  191 

iron,  185 

orange,  191 

yellow,  189 

yellow  dye,  189 

yellows,  dyeing  of,  165 
Chromic  acid.  185,  187 

acid,  action  on  indigo,  280 
Chromium,  185  • 

salts  of,  193 
Chrysaniline,  379,  381 

yellow,  382 
Chryso-rhamnine,  328 
Chrystoluidine,  379,  381 

yellows,  382 
Circumstances  influencing  affinity,  42 
Cinnabar,  202 

Citric  acid,  composition  of,  236 

for  printing,  146 
C.  Koechlin's  experiment,  384 
Clay  iron  stone,  151 
Clift's  green,  383 
Cloves,  composition  of  oil,  236 
Coal,  107 

gas,  111 

pit,  tansy  growing  in,  238 

tar,  acids  of,  374 

tar,  alkaloids  of,  374 

tar  colors,  dyeing  with,  389 

tar  colors,  general  remarks  on,  388 

tar,  composition  of,  373 

tar,  distillation  of,  374 

tar,  dyes  from,  374 

tar,  neutral  substances  of,  374 
Cobalt,  162 

nitrate  of,  effect  on  alumina,  148 
Coccus,  371 

cacti,  365 

ficus,  370 

loco,  370 
Cochineal,  365 

adulteration  of,  369 

affinity  of,  369 

alumina  mordants  with,  369 

analysis  of,  366 

Anthon's  method  of  valuing,  367 
German  experiments  on,  369 
Robiquet's  method  of  valuing,  367 
wild,  366 
value  of,  367 

Coke,  107 

Colorimeter,  336 

Colorine,  340,  343 

Coloring  matters,  madder,  338 
hypotheses  on,  234 
power  and  nature  of  aniline  colors, 
391 

principles  of  madder,  344 


Colors,  action  of  bases  upon,  218 
absorbed  by  charcoal,  107 
adjective,  220 

Bancroft's  arrangement  of,  220 
contrast  of,  31 
effect  of  heat  on,  23 
fast,  221 
fugitive,  221 
of  flowers,  240 
from  annotta,  350 
from  carbolic  or  phenic  acid,  385 
from  coal  tar,  373 
from  naphthaline,  387 
from  vegetables,  cause  of,  237 
from  wongshy,  362 
saddened,  247 
simple,  26 
substantive,  220 
Combustion,  oxygen  a  supporter  of, 
49 

with  tin  and  copper,  168 
Commercial  alizarine,  346 

indigoes,  274 
Common  iron  ores,  151 
Complementary  colors,  31 
Composition  of  blue  coloring  matters, 
309 

of  brezilin,  &c,  316 

of  catechu,  255,  256,  258 

of  coal  tar,  373 

of  products  of  indigo  and  nitric 
acid  and  chlorine,  282 

of  quercitrine,  324 

of  sandal  wood,  317 

of  vegetable  substances,  235 

of  white  indigo,  278 
Compositions  of  the  copperas  vat,  305 
Compounds,  rules  for  naming,  37 
Conditions  of  matter,  18 
Constitution  of  salts,  44 
Contrast  of  colors,  31 
Copper,  167 

acetate  of,  228 

arsenite  of,  197 
Copperas,  155,  156 

effect  of  light  on,  30 

preferable  as  a  mordant,  159 

vats,  305 

white,  165 
Copper  boilers  lined  with  tin,  177 

detected  in  copperas,  156 

effect  of  salts,  on  catechu,  255 
Coralline,  386 

Cordillot's  experiments,  384 
Cornwall,  tin  mines  of,  176 
Coromandel  indigoes,  275 
Corrosive  sublimate,  202 
Cotton,  211 

animalizing,  222 

dyeing  with  manganese,  150 


INDEX. 


409 


Cotton — 

goods,  bleaching  of,  398 

mordant  for,  228 

tests  for,  213 
Crajuru,  359 

Cream  of  tartar  as  a  mordant,  228 
Creosote,  375 
Crofting,  76 

theory  of,  77 
Cropped  madder,  334 
Crude  naphtha,  375 
Crum,  composition  of  indigo,  277 

on  indigo  with  sulphuric  acid,  284 

on  testing  indigo,  268 
Crura' s  chlorimeter,  87 

method  of  chlorimetry,  86 
Cubic  nitre,  130 
Cudbear,  352 
Cupeilation  of  lead,  170 
Cupro-ammoniacal  liquor,  action  on 

fibres,  213 
Cups  of  acorns,  258 
Curcuma  longa,  328 
Curcumine,  328 

Curd  of  milk  as  a  mordant,  396 

Cyanate  of  potash,  123 

Cyanides,  110 

Cyanogen,  110 

Cyanogen,  46 

Cyanide  of  potassium,  123 

Cynips,  242 

Dampness  produced  by  chloride  of  zinc, 
165 

Dana's  process  of  selecting  indigo,  267 
Danger  from  arsenic,  197 

from  arsenites  of  copper,  169 
Davy  on  galls,  242 
Dead  cotton,  211 

.    oil,  374 
Drebbel's  discovery  of  value  of  tin  as  a 

mordant,  176 
Decaisne  on  madder,  344 
Deception  in  galls,  249 
Decoction, of  Brazil  wood,  316 
Decoctions  of  logwood,  310 
Decoctions,  preparation  of,  311 
Decolorizing  indigo  as  a  test,  273,  274 
Decomposition  of  gallic  acid,  243 
Defects  in  indigoes,  276 
De  Laire's  brown  maroon,  385 
Deoxygenated  indigo,  264 
Dephlogisticated  muriatic  acid,  68 
Depouilly  process,  396 
Detection  of  alumina,  148 

of  cobalt,  163 

of  impurities  in  litharge,  170 
in  sulphate  of  copper,  168 
Determination  of  aniline  colors,  391 
of  value  of  bleaching  powder,  81 


Detonation  of  isopurpurates,  336 
Detonating  qualities  of  picric  acid,  280 
Deutoxide  of  tin,  178 
Dextrine  in  sizing  warps,  398 
Diagram  of  colors,  32 
Diamond,  107 
Didymium,  210 

Difference  in  quality  of  red  liquor,  145 
Differences  between  an  element  and 

compound,  34 
Dingier  on  decoctions  of  Brazil  wood, 

326 

Dinoxide  of  copper,  167 
Diphenylic  rosaniline,  379 
Dissolving  salts,  55 
Distillation  of  coal  tar,  374 

of  water,  51 
Divi  divi,  258 
Doctored  logwood,  311 
Double  muriates  of  tin,  181 
Dumas,  composition  of  indigo,  277 

on  indigoes,  274 

on  sulph-indylic  acid,  238 

plan  to  test  soap,  133 

process  for  indigo,  397 

theory  for  varieties  of  copperas,  154 

theory  of  composition  of  white 
indigo,  278 

theory  of  mordants,  228 
Dung  substitute,  103 
Dutch  madder,  334 
Dye  from  uric  acid,  372 
Dye-houses,  vats  in,  291 
Dyeing  affected  by  quality  of  water, 
247 

black  with  sumach,  250 

chemistry  necessary  in,  216 

Prussian  blue,  120 

silks  and  woollens  blue,  286 

study  necessary  in,  233 

temperature  for,  390 

with  barwood,  319 

with  coal  tar  colors,  389 

without  mordants,  395 

with  safflower,  330 

with  woad  and  pastel,  292 

with  wongshy,  361 
Dyes  from  coal  tar,  374 
Dye-woods,  tannin  in,  259 

Earth,  oxygen  in,  47 

Earths  proper,  137 

East  Indian  galls,  248 

Effects  of  different  rays  upon  colors,  27 

of  light  causing  combination,  28 
Effect  of  nitrate  of  cobalt  on  alumina, 
148 

Egypt,  indigo  of,  276 
Elective  affinity  in  dyeing,  324 
Electricity  in  mordanted  goods,  146 


410 


INDEX. 


Elementary  substances,  47 
Elements  of  matter,  34 

of  vegetable  substances,  234 
Embroideries,  imitation  of,  396 
Emeraldine,  383 
Emetic  tartar,  200 
England,  indigo  prohibited  in,  260 
English  copperas  best,  156 
Epsom  salt,  136 
Erbium,  210 

Erdmann  collects  and  names  haematein 
308 

Erdmann's  process  to  obtain  coloring 

matter  from  logwood,  307 
Error  in  selecting  copperas,  155 
Erythrozym,  344 
Essential  salt  of  lemons,  118 
Evil  spirit  of  the  mines,  162 
Experiments  on  gases  from  indigo,  263 

on  reaction  of  iron  and  tannin,  252 

with  flowers,  240 
Explosive  nature  of  picrates,  386 
Exposition,  reports  on,  395 
Extracting  alizarin,  337 

coloring  matter  of  indigo,  261 
Extraction  of  annotta,  349 

of  gold  from  ore,  205 

of  iron  from  ore,  151 

of  silver  from  ore,  203 
Extract  of  indigo,  283,  285 

of  logwood,  307,  308 

of  safflower,  332 
Extracts  of  woods,  326 

Fabric,  relation  of  colors  to,  26 

Fabrics,  textile,  211 

Fancy  shade,  to  dye,  75 

Fast  colors,  221 

Feather  bleaching,  396 

Fermentation  injures  gall-dyes,  243 

Ferricyanide  of  potassium,  122 

Ferrocyanide  of  potassium,  119 

Ferrocyanides,  120 

Ferro-prussic  acid,  119 

Fibres,  action  of  alloxane  on,  213 

bichloride  of  tin  on,  213 

caustic  potassa,  213 

cupro-ammoniacal  liquors  on, 
213 

muriatic  acid  on,  213 
nitric  acid  on,  213 
Fire-proof  fabrics,  194 
Firing,  226 
Fixed  green,  383 
Flavine,  325 
Flax,  211 

tests  for,  213 
Flints,  106 

Flowers,  coloring  matters  of,  240 
of  madder,  346 


Flowers — 

of  sulphur,  94 
Fluorine,  105 
Fluor  spar,  105 
Fluosilicic  acid,  105 
Fraud  in  galls,  249 
Fremy's  third  oxide  of  iron,  151 
French  purple,  354 
Fuchsine,  380 
Fugitive  colors,  221 

nature  of  gallates,  243 
Fuming  sulphuric  acid,  96 
Furs,  212 
Fusteric,  323 
Fustet,  322 
Fustic,  321 

young,  322 

Gallic  acid,  242 

composition  of,  236 

decomposition  of,  243 

not  largely  in  vegetables,  243 
Galls,  241 

Aleppo,  248 

analysis  of,  249 

Antoine's  experiments  with,  244 
best,  248 
black,  248 
choice  of,  248 
green,  248 

Guibourt's  analysis  of,  249 

kinds  of,  248 

loss  of  color  from,  243 

markets  for,  248 

marmorated,  248 

mixed,  248 

natural,  248 

selecting,  248 

varieties  of,  248 

white,  248 
Gall-nuts,  248 
Gall-wasp,  242 

Galvanic  action  in  boilers,  177 
Garancine,  340 

patent  for,  341 

reactions  with,  343 
Gases  absorbed  by  charcoal,  107 

formed  in  making  indigo,  263 

solution  of,  57 
Gelatine  as  a  mordant,  390 
General  effects  of  heat,  19 
Generalities  on  textile  fabrics,  213 
General  properties  of  matter,  18 

remarks  on  coal-tar  colors,  388 
German  experiments  on  cochineal,  369 

silver,  112,  163 

vat,  300 
Girardin  on  barwood,  317 
Girard  and  De  Laire's  purple,  381 
Glauber  salts,  129 


INDEX. 


411 


Gluten,  266 
Glossary,  399 
Gold,  205 
Gossypiuru,  211 
Grain  tin,  176 
Graphite,  107 

Gray  for  animal  fibres,  397 

mauveine,  385 
Grays,  aniline,  384,  385 

mureine,  385 
Greeks  early  used  indigo,  260 
Green  a  compound  color,  237 

alizarine,  345 

chrome,  191 

fast,  Williams'  discovery  of,  327 
from  arsenic,  197 
from  fustic,  322 

fruits,  excess  of  oxygen  in,  236 

picric  acid,  386 

printing  aniline,  397 

Scheele's,  169 

vitriol,  152 
Greens,  aniline,  383 

dyeing  by  chemic,  237 

picric  acid,  386 
Guatimala  indigoes,  276 
Gum  and  sugar  same  in  composition, 
235 

Gutta  percha  to  prevent  sores  from 

chrome  and  lead,  193 
Gypsum,  necessary  sometimes  in  water, 

248 

Hsematein,  308 
Hoematine,  306 
Hematoxylin,  306 
Hxmatoxylon  campeachiacum,  306 
Hard  water,  52 
Harmonizing  colors,  32 
Hartshorn,  67 

Hausm arm's  experiment,  223 
Heat,  18 

effect  on  colors,  23 

the  cause  of  conditions  of  matter, 
18 

Heavy  oil,  374 
Heavy  spar,  134 
Hemp,  212 

Hindoo  method  of  using  morinda,  357 
H.  Kcechlin  on  aniline  greens,  397 
XL  Koechlin's  leucaniline  brown,  385 
Hofmann's  blues  and  violets,  382 
Hunter  on  morinda,  357 
Hunt's  experiments  with  vegetables, 
238 

Husks  of  nuts  for  dyeing,  259 
Hydrated  ether  with  barwood,  319 
Hydrate  of  lime,  135 
Hydrated  protoxide  of  anyle,  278 
Hydrates,  40 


Hydriodic  acid,  104 
Hydrobromic  acid,  105 
Hydrocarbons,  111 
Hydrochlorate  of  ammonia,  67 
Hydrochloric  acid,  70 
Hydrocyanic  acid,  110 
Hydrofluoric  acid,  105 
Hydrotluosilicic  acid,  106 
Hydrogen,  49 

arseniureted,  199 

binoxide  of,  58 

favors  formation  of  sugar,  236 
Hydrogenation  of  indigo,  300 
Hydrometer,  64,  65 

not  reliable,  145 
Hyperchloric  acid,  70 
Hyperoxymuriates,  70 
Hypochlorates,  70 
Hypochloric  acid,  69 
Hypochlorous  acid,  69 
Hypophosphorous  acid,  103 
Hyposulphuric  acid,  101 
Hyposulphurous  acid,  100 
Hypothesis  on  coloring  matters,  234 

Ibiripitanga,  314 

Identification  of  aniline  colors,  392 

Imitation  of  embroideries,  396 

Imperial  purple,  381 

Improvement  in  bleaching  calicoes,  398 

Impure  alizarine,  343 

Impurities  in  catechu,  256 

in  hydrochloric  acid,  72 

in  indigo,  265 

in  madder,  346 

in  nitric  acid,  64 

in  sulphate  of  copper,  168 

of  water,  52 
Increase  in  weight  of  silk  by  dyeing, 
395 

Indian  vat,  295,  299 

Indicum,  260 

Indigo,  260 

action  of  alkalies  on,  277 
action  of  chemicals  on,  277 
action  of  chlorine  on,  281 
action  of  chromic  acid  on,  280 
action  of  nitric  acid  on,  280 
action  of  salts  on,  277 
action  of  sulphuric  acid  on,  283 
action  of  water  on,  277 
adulteration  of,  273 
Berthollet  on  fermentation  in,  263 
Berzelius'  mode  of  selecting,  266 
blue,  292 

blue,  composition  of,  309 

Bolley's  test  for,  273 

brown,  266 

characteristics  of,  277 

chemical  changes  in  making,  263 


INDEX. 


chemical  composition  of,  277 
Chevreul's  mode  of  selecting,  266 
chlorine  to  test,  273 
chloroform  as  a  solvent  for,  397 
composition  of  products  of,  by  nitric 

acid  and  chlorine,  282 
Crum's  analysis  of,  277 
Crum's  test  for,  268 
Dana's  mode  of  selecting,  267 
decolorizing  as  a  test,  273,  274 
deoxygenated,  264 
Dumas'  analysis  of,  277 
Dumas'  process  for,  397 
early  used  by  Greeks,  260 
early  used  by  Romans,  260 
extract,  283,  285 

adulteration  of,  286 
extracting  coloring  matter  of,  261 
extract  of,  283,  285 
hydrogenation  of,  300 
impurities  in,  265 
Kane  on  changes  in,  263 
manufacture  of,  261 
nature  of,  265 
Penney's  test  for,  274 
prohibited  in  England,  260 
properties  of  pure,  268 
purification  of,  397 
purifying,  397 
red,  266 

Reinsh's  tests  for,  272 
sampling,  266 

Schlumberger's  method  for  pure, 

269 
Senegal,  276 

starch  used  to  adulterate,  273 
sublimation  of,  268 
Taylor's  method  for  pure,  269 
tests  for,  266,  267,  268,  269,  272 
Thomson  on  changes  in,  263 
to  ascertain  quality  of,  266 
to  know  value  of,  266,  267 
Ure  on  gases  from,  263 
value  of,  271 
white,  277 

white,  composition  of,  309 
white  lead  used  to  adulterate,  273 
with  sulphuric  acid,  284 
igoes,  Caraccas,  276 
Carolina,  276 
Chevreul  on,  274 
commercial,  274 
defects  in,  276 
Dumas  on,  274 
from  Africa,  276 
from  America,  276 
from  Asia,  275 
from  Egypt,  276 
Guatimala,  276 


Indigoes — 

of  Bengal,  275 

of  Brazil,  276 

of  Coromandel,  275 

of  Java,  276 

of  Madras,  275 

of  Manilla,  275 

of  Mexico,  276 
Indigofera,  260 
Indigogen,  287 
Indigotic  acid,  279,  282 
Indisine,  381 

Ingredients  of  annotta,  349 

Ink,  permanent,  204 

Inks,  sympathetic,  162 

Intermediate  oxides  of  iron,  254 

Iodic  acid,  104 

Iodide  of  ethyl  green,  383 

Iodide  of  potassium,  colors  from,  27 

Iodine,  104 

Iodine  blues  and  violets,  382 
Iridium,  208 
Iron,  151 

acetate  of,  157 

bisulphate  of,  155 

bisulphuret  of,  154 

carbonate  of,  157 

chloride  of,  157 

chrome,  185 

deleterious  in  manganese,  150 
effect  of  salts  on  catechu,  255 
extracted  from  sulphate  of  man- 
ganese, 150 
liquor,  157 
mordant,  215 
nitrate  of,  158 
nitrate  of,  to  prepare,  227 
peracetate  of,  161 
peroxalate  of,  161  . 
persalts  of,  158 
persulphate  of,  158,  162 
per  tartrate  of,  161 
protosalts,  161 
pyrites,  154 

pyrolignite  of,  157  " 
sulphate  of,  152 
sulphate  of,  as  a  mordant,  228 
and  alumina,  acetate  of,  227 
and  tin  for  royal  blue,  227 

Isatine,  280,  282 

Isatinic  acid,  280,  282 

Isatis  tinctoria,  260 

Isomeric  bodies,  235 

Isopurpurates,  386 

detonation  of,  386 

Isopurpuric  acid,  386 

Ivory,  black,  107 


Jacobsen's  brown,  387 
Jamaica  wood,  306 


INDEX. 


413 


Java  indigoes,  276 
Jaune  d'or,  387 

John's  analysis  of  cochineal,  366 
examination  of  annotta,  349 
Judging  logwood,  312 
Julian  and  Roquer  introduce  flowers  of 
madder,  346 

Kane  on  changes  in  indigo,  263 
Kane's  theory  of  bleaching,  91 
Kaolin,  141 

Kermes,  reactions  of,  371 
Kerms,  371 
Killed  iron,  227 
Killing  iron,  160 
King's  yellow,  198 
Kobalds,  162 

Koechlin  C,  bath  for  dyeing  cotton  or 

silk,  384 
Koechlin,  C,  experiments,  384 
Koechlin,  H.,  on  aniline  greens,  397 

leucaniline  browns,  385 
Kopp's  production  of  alizarine,  345 
Kuhlmann's  xanthine,  344 

Lac,  370 

dye,  370 

lac,  370 

spirits,  371 
Lacs,  371 

Lake,  aluminous,  354 

lake,  370 
Lampblack,  107 
Lanthanium,  210 
Laurent  on  naphthaline,  387 
Lauth's  experiments,  384 
Lavenders  from  safnower,  331 
Lead,  169 

basic  salts  of,  172 

chromate  of,  189 

chromate  of  as  a  mordant,  397 

effect  of  salts  on  catechu,  255 

salts,  value  of,  174 

white,  to  adulterate  indigo,  273 
Leaves  absorb  oxygen,  239 

why  they  change  in  autumn,  239 
Lemon  juice,  composition  of,  236 
Lepidolite,  131 
Leucaniline,  379 

brown,  385 
Levant  madder,  334 
Libi  davi,  258 
Lichen  roccella,  352 
Liebig  on  presence  of  nitrogen,  234 

on  reaction  of  indigo,  278 
Light,  25 

action  of  on  nitric  acid,  63 

affects  colors,  29 

changes  color  of  plants,  238 


Light — 

decomposes  chemical  compounds, 
29 

Lightfoot's  black,  384 

chlorine  process,  396 
Light  oil,  374 
Lilacs,  from  safflower,  331 
Lima  wood,  315 
Lime,  135 

chloride  of,  80 

in  blue  vat,  291 

in  cl^eing  with  sumach,  251 

objectionable  in  using  acetate  of 
lead,  172 

and  casein  as  a  mordant,  223 
Limes,  quality  required,  305 
Limestone,  136 
Lime-water,  135 

on  logwood,  311 
Linum  usitatissimum,  211 
Liquids,  boiling  of,  21 
Liquor  chica,  359 
Litharge,  170 
Lithia,  130 

Lithospermum  tinctorium,  352 

Lithium,  130 

Localities  of  tin  ore,  176 

Logwood,  306 

chemical  investigation  of,  309 
Chevreul's  examination  of,  306 
Chevreul's  process  to  obtain  the  co- 
loring matter  from,  307 
decoctions,  310 

Parkes  on,  311 
doctored,  311 

Erdmann's  process  to  obtain  the 

coloring  matter  of,  307 
extract,  307,  308 

forbidden  by  Queen  Elizabeth,  306 

judging,  312 

lime-water  on,  311 

reactions  on,  309 

scalding,  310 

testing,  312 

value  of,  312 
Lowe's  green,  383 
Luminous  rays,  25 
Lunar  caustic,  204 
Luleo- gallic  acid,  249 
Luteoline,  327 
Lythrum  fruticosum,  357 

MacCulloch,  distinction  between  bar- 
wood  and  camwood,  317 
Madder,  333 

adulterations  of,  336,  346 

Alsace,  335 

Avignon,  335 

bones  colored  by,  338 

brown,  339 


414 


INDEX. 


Madder — 

coloring  matters,  338 
coloring  principles,  344 
cropped,  334 
Decaisne  on,  344 
Dutch,  334 

extract,  Pernod  and  Picard's,  397 

extract,  Rochleder's,  397 

extract,  Schutzenberger's,  398 

extracts,  values  of,  397 

flowers  of,  346 

Levant,  334 

marks  of,  335,  336 

Meissonnier's  extracts,  398 

mordants  for,  344 

orange,  339 

Pernod's  test  for,  346 

preparations,  340 

purple,  338 

qualities  of,  334 

red,  338 

sampling,  347 

Schutzenberger  on,  344 

silk  printing  with,  346 

tests  for,  336 

uncropped,  334 

urine  colored  by,  338 

useful  products  of,  339 

varieties  of,  334 

yellow,  339 
Madderic  acid,  339 
Madras  indigoes,  275 
Magenta,  380 
Magnesia,  136 

in  mordanting,  224 

objectionable  in  limes,  305 
Magnesia  nigra,  149 
Magnesium,  136 
Mahogany  sawdust,  259 
Malabar  catechu,  256 
Malvaceso,  211 
Management  of  vats,  302 
Manchester  yellow,  387 
Manganese,  149 

chloride  of,  150 

how  detected,  151 

oxides  of,  149 

sulphate  of,  149 
Mangrove  bark,  258 
Manilla  indigoes,  275 
Manipulations  of  mordants,  147 
Manufacture  of  aniline,  376 

of  indigo,  261 

of  indigo  extract,  285 

of  soap,  131 
Marine  acid.  70 
Marks  of  madder,  335,  336 
Mamas'  process  for  French  purple, 
353 

Maroons,  aniline,  383 


Martius'  yellow,  387 
Matter,  18 
Mauvaniline,  381 
Mauve,  381 
Mauveine,  379 

gray,  385 

sulphate  of,  381 
Measures  of  temperature,  19 
Meissonnier's  madder  extracts,  398 
Mellon,  111 
Mellonides,  111 
Mercer's  experiments,  213 
Mercury,  202 

Metallic  oxides,  action  on  logwood,  309 

salts,  action  on  galls  or  sumac,  246 

substances,  112 
Metals,  112 

action  on  Brazil  dye,  316 

proper,  149 
Method  of  obtaining  tannin  from  galls3 
242 

Mexico,  indigoes  of,  276 
Meyer  process,  396 
Mimosa  used  in  dyeing,  357 
Mineral  alkali,  123 
chameleon,  150 
Minium,  171 
Mistic,  366 

Modified  pastel  vat,  298 
Molybdenum,  195 
Molybdic  acid,  195 
Monophenylic  rosaniline,  379 
Mordant,  144 

alum,  228 

alumina,  215 

bitartrate  of  potash  as,  228 

casein  as,  396 

chloride  of  tin  as,  228 

chrome  as,  192 

copperas  as,  159 

cream  of  tartar  as,  228 

for  cotton,  228 

for  woollens,  228 

iron,  215 

repose  after,  229 

Roman  alum  as,  228 

sulphate  of  iron  as,  228 

test  of,  145 

tin,  215 

tin  as,  176 

value  of  alum  as,  138 
Mordanted  goods,  electricity  of,  146 
Mordants,  214 

action  of,  228 

alum,  145 

bases  as,  215 

choice  of,  215 

Dumas'  theory  of,  228 

for  Brazil  wood,  317 

for  coal-tar  colors,  390 


INDEX. 


415 


Mordants — 

for  coal  tar  colors  on  vegetable 
fibres,  395 

for  madder,  344 

for  printing,  224 

manipulations  of,  147 

not  required  for  archil,  353 

oxides  as,  215 

phenomena  from,  146 

properties,  232 

solution  of,  215 

theory  of,  228 
Morin,  321 

Morinda  citrifolia,  357 

Hindoo  method  of  using,  357 

Hunter  on,  357 
Morindine,  analyses  of,  356 

chocolate  from,  357 

purple  from,  357 

solution  of,  356 
31orus  tinctoria,  321 
Mosul  galls,  248 
Mottled  soap,  131 
Mucilaginous  compounds,  236 
Mull,  334 
Munjeet,  348 
Mureine  grays,  385 
Murexide,  371 

reactions  of,  372 
Muriates,  71 
Muriatic  acid,  70 

acid,  action  on  fibres,  213 
Myrobalans,  258 

used  in  dyeing,  357 

Naming  compounds,  37 
Nankeen  dye,  Scott's,  351 

from  nitrate  of  iron,  159 
Naphtha,  375 

crude,  375 

solvent,  375 
Naphthalamine,  387 
Naphthaline,  375 

alizarin  from,  387 

colors  from,  387 

Laurent  on,  387 
Naphthylamine,  387 

yellow,  387 
Native  ores  of  arsenic,  198 
Nature  of  indigo,  265 

of  light,  25 

of  salt,  39 
Neapolitan  silk,  analysis  of,  222 
Nerium  Tinctorium,  260 
Neutral  substances  of  coal  tar,  374 
New  vegetable  dyes,  355 
Nicaragua  wood,  315 
Nicholson's  purple,  381 
Nickel,  163 

carbonate  of,  164 


Nickel — 

chloride  of,  164 

nitrate  of,  164, 

sulphate  of,  164, 
Night  blue,  382 

green,  383 
Niobium,  210 
Nitrate  of  ammonia,  62 

of  barytes,  134 

of  bismuth,  175 

of  cobalt,  effect  in  alumina,  148 

of  copper,  168 
of  iron,  158 

of  iron,  to  prepare,  227 

of  lead,  171 

of  nickel,  164 

of  potash,  62,  118 

of  silver,  204 

of  silver,  effect  of  light  on,  29 

of  soda,  62,  124,  130 

of  strontium,  135 

of  tin,  178 

of  zinc,  165 
Nitrates,  action  on  Brazil  dye,  316 

deposits  of,  62 
Nitre,  64 
Nitric  acid,  61 

acid,  effect  of  light  on,  29 

acid,  action  on  fibres,  213 

acid,  action  on  indigo,  280 

acid,  in  dyeing,  225 
Nitrogen,  58 

chloride  of,  74 

not  in  coloring  matters,  235 
Nitromuriate  of  tin,  225 
Nitrous  acid,  61 
Nomenclature,  37 
Nordhausen  acid,  96 
Normandy  on  soap,  133 
Nuts,  gall,  248 

valonia,  258  * 

Oak  bark,  258 
Objections  to  arsenic,  197 
Odor,  a  guide  in  preparing  vats,  296, 
301 

Oil,  dead,  374 
heavy,  374 
light,  374 

of  cloves,  composition  of,  236 
of  potatoes,  composition  of,  236 
of  sesamum,  used  in  dyeing,  357 
of  turpentine,  composition  of,  236 
with  casein  and  lime,  223 

Olefiant  gas,  111 

Orange,  aniline,  382 
chrome,  191 
dye,  189 

from  acetate  of  lead,  172 
from  lead,  171 


416 


INDEX. 


Orange — 

madder,  389 

victoria,  382 
Orceine,  353 

composition  of,  309 
Or  cine,  353 

Ordway's  analysis  of  iron  crystals,  161 
Ore  of  antimony,  199 

of  molybdenum,  195 
Ores  containing  silver,  203 

of  arsenic,  196 

of  mercury,  202 

of  tin,  176,  179 
Orpiment,  198 
Osmium,  209 
Oxalate  of  copper,  169 

of  potash,  118 

of  potash  and  chrome,  110 

of  tin,  183 
Oxalates,  109 
Oxalic  acid,  109 
Oxide  of  cadmium,  166 

of  copper,  167 

of  ianthanium,  210 

of  sodium,  124 

of  zinc,  165 
Oxides  of  antimony,  199 

of  arsenic,  196 

of  bismuth,  175 

of  cerium,  201 

of  chromium,  185 

of  cobalt,  162 

of  gold,  205 

of  iridium,  209 

of  iron,  151 

of  iron,  intermediate,  254 

of  lead,  170 

of  manganese,  149 

of  mercury,  202 

of  molybdenum,  195 

as  mordants,  215 

of  nickel,  163 

of  osmium,  209 

of  palladium,  208 

of  platinum,  207 

of  rhodium,  209 

of  silver,  204 

of  tellurium,  196 

of  tin,  177 

of  titanium,  184 

of  tungsten,  194 

of  uranium,  200 

of  vanadium,  1^4 
Oxidizing  vegetable  matters,  168 
Oxychloride  of  antimony,  199 

of  tin,  177,  180 
Oxygen,  47 

action  in  dyeing  black,  251,  252 

causes  acid,  236 

combinations  with  iron,  151 


Oxygen — 

false  use  of  the  word,  79 

gas,  to  make,  48 
Oxygenized  muriatic  acid,  68 
Oxymuriatic  acid,  68 
Ozone,  93 

Palladium,  207 

Pao  da  rain  ha,  314 

Paraf  and  Javal  process  for  black,  397 
Parkes  on  frauds  in  copperas,  155 

on  logwood  decoctions,  311 
Paste  for  calico  printing,  345 

for  printing  aniline  black,  397 
Pastel,  292 

vat,  294 
Patent  for  garancine,  341 

for  preparing  aloes,  363 
Peachwood,  314 
Pearlash,  114 
Peel  of  walnuts,  259 
Pelopium,  210 

Penney's  method  of  testing  indigo,  274 

test  for  tin,  180 
Peonine,  386 
Pelouze  on  galls,  242,  243 
Peracetate  of  iron,  161 
Perchloride  of  gold,  216 

of  mercury,  202 

of  tin,  180 
Perhydrate  hematoxylin,  composition 
of,  309 

Perkins'  aniline  violet,  381 

mauveine,  379 

yellow,  387 
Permanent  ink,  204 
Permanganate,  alkaline,  396 
Permuriate  of  tin,  180 
Pernambuco  wood,  315 
Pernod's  test  for  madder,  346 
Pernod  and  Picard's  madder  extracts, 
397 

Peroxalate  of  iron,  161 
Peroxide  of  gold,  205 

of  lead,  171 

of  mercury,  202 

of  molybdenum,  195 

of  nitrogen,  61 

of  palladium,  208 

of  platinum,  207 

of  silver,  204 

of  tin,  179 

of  uranium,  201 
Persalts  of  iron,  158,  162 

of  mercury,  202 

of  platinum,  207 
Persian  berries,  328 
Persis,  352 

Persoz  on  reaction  of  iron  and  tannin, 
252 


INDEX. 


4L7 


Persoz — 

peonine  or  coralline,  385 
Persulphate  of  iron,  158 
Pertartrate  of  iron,  161 
Petitclidier's  imitation  of  embroideries, 
396 

Phenic  acid  colors,  385 

Phenicienne,  386 

Phenomena  from  mordants,  146 

Phinacin,  283 

Phoenicians  use  tin,  176 

Phosphate  of  potash,  118 

Phosphates  attraction  for  alizarin,  338 

Phosphides,  103 

Phosphine,  382 

Phosphoric  acid,  103 

Phosphorus,  103 

Phosphorous  acid,  103 

Phosphurets,  103 

Photography,  29 

Picrates,  explosive  nature  of,  386 
Picric  acid,  280,  386 

brown,  387 

greens,  386 
Pincoffine,  346 

Pink,  from  saffiower,  330,  331 
Pipe-clay  as  a  thickening,  147 
Pittacal,  364 

Plants  absorb  oxygen,  239 
Platinum,  206 
Platinum  soldering,  165 
Plumbago,  107 
Plumb  spirits,  183,  226 

tubs,  310,  313 
Pohl's  method  of  identifying  aniline  col- 
ors, 392 
Poison  by  arsenic,  197 

from  salts  of  copper,  169 
Poisonous  effects  of  lead  salts,  173 
Potash,  113 

alum,  139 

bichromate  as  a  mordant,  228 

bitartrate  as  a  mordant,  228 

chromate  of,  187 
Potatoes,  composition  of  oil,  236 
Potash,  nitrate  of,  62 

tellurate  of,  196 

specific  gravity  of,  116 

vats,  293,  300 
Potassa,  effect  of  bichromate  on  cate- 
chu, 255 

isopurpurate  of,  386 
Potassium,  113 
Potato  affected  by  light,  238 
Practical  application  of  chemistry,  30 
Precipitates  affected  by  light,  30 

by  alumina  salts,  148 

from  zinc  salts,  165 
Preisser  favors  Liebig's  theory  on  in- 
digo, 279 
27 


Preisser — 

on  barwood,  317 

on  Brazil  woods,  316 
Preparation  of  decoctions,  311 

of  lake,  370 
Preparing  aloes,  363 

archil,  352 

the  blue  vat,  291 
Preparations  of  madder,  340 
Printing  aniline  greens,  397 

mordants  for,  224 

paste,  384 

paste  for  aniline  black,  397 
without  Jacquart  loom,  396 
works,  vats  in,  291 
Prismatic  colors,  26 
Processes  for  selecting  indigo,  266,  267 
Process  of  dyeing  black  with  sumach, 
250 

Prohibition  of  indigo,  260,  261 
Properties  of  metals,  112 

of  mordants,  232 

of  oxygen,  49 

of  pure  indigo,  268 
Proposed  new  vegetable  dyes,  355 
Protochloride  of  palladium,  208 

of  platinum,  207 

of  tin,  121,  177 
Protohydrate    hsematoxylin,  composi- 
tion of,  309 
Protonitrate  of  iron,  160 

of  tin,  178 
Protosalts  of  iron,  161 
Protosulphate  of  tin,  178 
Protoxide  of  cadmium,  166 

of  copper,  167 

of  lead,  170 

of  mercury,  202 

of  nitrogen,  60 

of  palladium,  208 

of  platinum,  207 

of  silver,  204 

of  tin,  177 

of  uranium,  200 

of  zinc,  165 
Prussian  blue,  120 

from  nitrate  of  iron,  159 
Puces,  from  safflower,  331 
Pure  clay,  141 

indigo,  properties  of,  268 

water,  51 
Purification  of  indigo,  397 
Purity  of  soaps,  how  known,  133 
Purple,  French,  354 

from  morindine,  357 

imperial,  381 

madder,  338 

regina,  381 
Purples  from  naphthaline,  387 
Purpurate  of  ammonia,  371 


418 


INDEX. 


Purpurine,  345 
Purwas  used  in  dyeing,  357 
Pyrites,  iron,  to  make  copperas,  153 
Pyroligneous  acid,  144 

with  lead,  172 
Pyrolignite  of  alumina,  227 

of  iron,  157,  227 
Pyroxylic  spirit,  composition  of,  236 

with  barwood,  319 

Qualities  of  catechu,  255 

of  madder,  334 
Quality  of  indigo,  to  ascertain,  266 

of  red  liquor,  difference  in,  145 

of  water  affects  dyeing,  247 
Quartz,  106 
Queen-wood,  314 
Quercitrine,  324 
Quercitron,  323 
Quercus  infectoria,  242 

nigra,  323 
Quicksilver,  202 

Radicals,  salt,  45 

Rain,  nitrate  of  ammonia  in,  62 

Raising,  217 

Reactions  of  alizarin,  337 
of  alkanet,  352 
of  catechu,  257 
of  cobalt  salts,  163 
of  flavine,  326 
of  indigo,  277,  278,  279 
of  kerms,  371 
of  logwood,  309 
of  murexide,  372 
of  quercitron,  323 
of  salts  of  bismuth,  175 

of  cadmium,  166 

of  cerium,  202 

of  chromium,  193 

of  gold,  206 

of  lead,  174 

of  mercury,  202 

of  molybdenum,  195 

of  nickel,  164 

of  palladium,  208 

of  platinum,  207 

of  silver,  205 

of  tellurium,  196 

of  tin,  184 

of  uranium,  201 

of  vanadium,  194 

of  zinc,  165 
with  annotta,  350,  351 
with  archil,  353 
with  barwood  solution,  318 
with  camwood,  321 
with  carmine,  366 
with  fustic,  322 
with  fustic  (young),  323 


Reactions — 

with  garancine,  343 

with  salts  of  copper,  169 

with  weld,  327 

with  wongshy,  360,  361 
Reagents  which  affect  salts  of  manga- 
nese, 151 
Realgar,  198 
Red  carthamine,  332 

chromate  of  potash,  188 

from  naphthaline,  387 

lead,  171 

liquor,  144 

difference  in  quality,  145 
varieties  of,  145 

madder,  338 

oxide  of  mercury,  202 

precipitate,  202 

prussiate  of  potash,  122 

spirits,  182,  224 

woods,  314,  320 
Reds  from  archil,  353 

from  munjeet,  348 
Regina  purple,  381 
Reimann,  dyeing  aniline  colors,  395 
Reinsh's  method  of  testing  indigo,  272 
Relation  of  colors  to  the  fabric,  26 
Reports  on  dyeing,  etc.,  395 
Repose  after  a  mordant,  229 
Resin  of  gamboge,  composition  of,  236 
Rhamnus  tinctoria,  328 
Rhodium,  209 
Rhus  cor iaria,  249 
Rhus  cotinus,  323 

Robinson's  discovery  of  a  plant  in  a 
coal-pit,  238 

Robiquet's  method  of  valuing  cochi- 
neal, 367 

Robiquet  and  Colin  on  garancine,  340 
Rochleder's  madder  extracts,  397 
Roman  alum  preferred  as  a  mordant, 
228 

vitriol,  168 
Romans  early  used  indigo,  260 
Roots  of  walnut,  259 
Rosaniline,  379,  380 

greens,  383 
Roseine,  380 
Rosin  soaps,  398 
Rothine,  386 
Roucou,  348 

Roussin's  alizarin  from  naphthaline,  387 

Royal  blue,  dyeing,  121 

Rubiacic  acid,  339 

Rubia  memsgista,  333 

Rubian,  344 

Rubia  tinctorium,  333 

Rubine,  380 

Ruby,  148 

soluble,  386 


INDEX. 


419 


Rules  for  naming  compounds,  37 
Ruthenium,  210 

Saccharine  compounds,  236 
Saddened  colors,  247 
Safflower,  329 
Sal-ammoniac,  67 

used  by  dyers,  183 
Salt,  124 

cake,  129 

of  sorrel,  109 

radicals,  45 

spirit  of,  70 
Salts,  action  on  indigo,  277 

action  of  metallic,  on  galls  or  su- 
mach, 246 

constitution  of,  44 

nature  and  nomenclature,  39 

of  alumina,  148 

of  cadmium,  1 66 

of  chromium,  186 

of  copper,  167 

of  strontium,  135 

of  tin,  121,  177,  180 

of  zinc,  165 

solution  of,  57 
Sampling  indigo,  266 

madder,  347 
Sand,  106 
Sandal  wood,  317 
Santal,  317 
Santaline,  317 
Santa  Martha  wood,  315 
Sapan  wood,  315 
Sapphire,  148 
Saturation,  55 
Saunders  wood,  317 
Saxon  blue,  283 
Scalding  logwood,  310 
Scarlet  from  tin,  176 
Scheele's  green,  169,  197 
Schiel's  analysis  of  morindine,  356 
Schinus,  359 

Schlumberger's  method   of  obtaining 

pure  indigo,  269 
Scott's  nankeen  dye,  351 
Schunck  on  rubian,  344 

and  Pincoffs  introduce  commercial 
alizarine,  346 
Schutzenberger  on  madder,  344 
Schtitzenberger's  madder  extracts,  398 
Seed-lac,  370 

Selection  by  dyers  of  copperas,  155 
Selenium,  103 
Senegal  indigo,  276 
Sesamum  orientate,  357 
Sesquioxide  of  tin,  178 
Shell-lac,  370 
Sicilian  sumach,  250 
Silica,  106 


Silicic  acid,  106 
Silicium,  106 
Silk,  212 

analysis  of  Neapolitan,  222 

printing  with  madder,  346 

weight  increased  by  dyeing,  395 
Silver,  203 

from  lead  ore,  170 

gray  for  animal  fibres,  397 
Simple  colors,  26 
Single  muriates  of  tin,  181 
Sizing  warps,  cjextrine  for,  398 
Slaked  lime,  135 
Sludge,  288 
Smalt  blue,  163 
Smyrna  galls,  248 
Soap,  131 

test  for  water,  53 
Soaps,  rosin,  398 
Soda,  123 

alum,  139 

aluminate  of,  141 

ash,  124,  125 

borate  of,  106 

nitrate  of,  62 

stanno-arsenite  of,  178 

tellurate  of,  196 

tungstate  of,  194 
Sodium,  123 
Soft  soap,  132 

water,  52 
Soldering  platinum  vessels,  165 

with  chloride  of  zinc,  165 
Solly  on  Barbary  root,  364 
Solubility  of  aniline  colors,  388 
Soluble  blues  or  violets,  389 

ruby,  386 
Solution  of  mordants,  215 
Solutions  affected  by  light,  30 
Solvent  for  aniline  blacks,  396 

naphtha,  375 
Solvents  for  aniline  colors,  388 
Sooranjee,  355 

Sores  from  chrome  and  lead,  193 
Source  of  water,  52 
Souring,  76 

Specific  gravity  of  potash,  116 
Spectrum,  26 
Spirit  of  salt,  70 
Spirits  of  tin,  181 
Spurious  catechu,  256 
Stackler  on  iron  mordants,  254 
Stannic  acid,  180 

oxide,  180 
Stanno-arsenite  of  soda,  178 
Stannous  salts,  177 
Starch  to  adulterate  indigo,  273 
Steaming  aniline  colors,  390 
Steam  rollers,  147 
Steeping,  75 


420 


INDEX. 


Stenhouse's  experiments,  241 

method  for   obtaining  dye  from 
lichens,  353 
Stein  on  wongshy,  359 
Sticking,  90 
Stick-iac,  370 

potash,  117 
Stream  tin,  176 
Strong  boiling,  22 
Strontia,  135 
Strontium,  135 

Study  necessary  in  dyeing,  233 
Subacetate  of  alumina,  147 
Subacetates  of  lead,  172 
Subchloride  of  copper,  167 

of  gold,  216 
Sublimation  of  indigo,  268 
Suboxide  of  copper,  167 

of  gold,  205 

of  lead,  170 

of  mercury,  202 

of  phosphorus,  103 

of  silver,  204 
Substances  affecting  boiling  point,  21 
Substantive  colors,  220 
Sugar,  composition  of,  235 

of  lead,  171 

and  gum  same  in  composition, 

235 

Sulphate  of  alumina,  141 
of  antimony,  199 
of  barytes,  134 
of  bismuth,  175 
of  cadmium,  166 
of  chromium,  186 
of  cobalt,  162 
of  copper,  167 
of  indigo,  283,  285 
of  iron,  152 

of  iron  as  a  mordant,  228 

of  lead,  173 

of  lime,  136 

of  manganese,  149 

of  mauveine,  381 

of  nickel,  164 

of  platinum,  207 

of  potash,  117 

of  silver,  204 

of  soda,  129 

of  tin,  178 

of  zinc,  165 
Sulphates  of  lime,  135 
Sulph-indylic  acid,  283 
Sulphion,  45 
Sulphite  of  potash,  118 
Sulphites,  alkaline  for  printing,  397 
Sulpho-purpuric  acid,  283 
Sulphur,  93 

Sulphuret  of  antimony,  199 
of  molybdenum,  195 


Sulphurets  of  arsenic,  198 

of  silver,  203 
Sulphuretted  hydrogen,  101 
Sulphuric  acid,  95 

acid,  action  on  indigo,  283 

acid  as  a  solvent  of  aniline,  388 
Sulphurous  acid,  94 
Sumach,  249 

dyes  injured  by  fermentation,  243 

Venetian,  322 
Sun,  acts  on  Brazil  dyes,  317 
Sweetening,  89 

Swimming,  in  the  blue  vat,  289 
Symbols,  36 
Sympathetic  inks,  162 

Table  of  condensation  of  sulphuric  acid, 
97 

of  quantity  of  acids  in  nitric,  &c, 
65 

of  solution  of  salts,  56,  57 
of  specific  gravity  of  hydrochloric 
acid,  72 

of  strength  of  sulphuric  acid,  99 

of  tests  for  water,  55 

of  thermometer  scales,  20 

of  value  of  bleaching  powder,  84 
Tannic  acid,  composition  of,  236 
Tannin,  242 

for  cotton  printing,  397 

in  dye  woods,  259 

precipitates  aniline  colors,  388 

superior  for  dyeing  black,  246 
Tansy  in  a  coal-pit,  238 
Tapestry,  imitation  of,  396 
Tartar,  cream  of,  as  a  mordant,  228 

emetic,  200 
Tartaric  acid,  composition  of,  236 
Tartrate  of  antimony  and  potassa,  200 

of  potash  and  tin,  178 
Taylor's  method  of  obtaining  pure  in- 
digo, 269 
Technical  terms,  glossary  of,  399 
Tellurate  of  potash,  196 

of  soda,  196 
Telluric  acid,  196 
Tellurites,  196 
Tellurous  acid,  196 
Tellurium,  196 
Temperature  for  dyeing,  390 

measures  of,  19 
Terbium,  210 
Terminalia  chebula,  357 
Terms,  glossary  of,  399 
Terra  japonic  a,  254 

Tessie  du  Motay  and  Marechal  on  alka- 
line permanganates,  396 
Test  for  oxalic  acid,  109 

for  quantity  of  tin,  180 

glass,  86 


INDEX. 


421 


Testing  copperas,  156 
logwood,  312 
madder,  336 
mordant,  145 
soap,  133 
soda-ash,  126 

the  value  of  lead  salts,  174 
Tests  for  alum,  139 
for  annotta,  351 
for  bichromate  of  potash,  1 93 
for  bleaching  powder,  81 
for  impurities  in  nitric  acid,  64 
for  indigo,  266,  267,  268,  269, 
272 

for  litharge,  170 

for  madder,  346 

for  silver,  204 
•    for  water,  53 

for  wool,  cotton,  flax,  &c,  213 
Textile  fabrics,  211 

fabrics,  generalities  on,  213 

fabrics  rendered  fire-proof,  194 
Thenard  and  Hoard's  experiments,  229 
Theories  of  composition  of  white  in- 
digo, 278 
Theory  of  aniline  colors,  377 

of  bleaching,  77 

of  mordants,  228 

of  the  blue  vat,  288 
Thermometers,  20 

Thorn  on  elective  affinity  of  coloring 

matters  and  bases,  324 
Thomson  on  changes  in  indigo,  264 
Tin,  175 

acted  on  by  nitrate  of  copper,  168 
chloride,  best  mordant  from  Bra- 
zil wood,  317 
chloride  of,  as  a  mordant,  228 
effect  of  salts  on  catechu,  255 
mordant,  215 

and  iron  for  royal  blue,  227 
Tinkal,  130 
Tinstone,  179 
Titanium,  184 

Tobacco  kept  moist  with  chloride  of 

zinc,  165 
Toluidine  greens,  383 
Tribasic  acetate  of  lead,  172 
Trinitrophenic  acid,  386 
Triphenylic  rosaniline,  379 
Tungstate  of  soda,  194 
Tungstenum,  194 
Tungstic  acid,  194 
Turkey  red  dyeing,  357 
Turmeric,  328 

Turpentine,  composition  of  oil,  236 
TwaddelPs  hydrometer,  64,  65 

Uncropped  madder,  334 
Union  of  elements,  35 


Universal  exposition,  dyeing  in,  395 
Uranium,  200 

Ure  on  gases  from  indigo,  263 
Uric  acid,  dye  from,  372 
Urine  colored  by  madder,  338 
Useful  products  of  madder,  339 
Use  of  potash  to  dyers,  114 

of  symbols,  36 
Uses  of  tin  in  dyeing,  176 

Valerianic  acid,  279,  282 

Valonia  nuts,  258 

Value  of  aniline  colors,  391 

of  cochineal,  367 

of  indigo,  271 

of  indigo,  to  know,  266,  267 

of  iron  liquor,  157 

of  lead  salts,  174 

of  logwood,  312 

of  varieties  of  copperas,  155 

of  wongshy  as  a  color,  361 
Values  of  madder  extracts,  397 
Vanadic  acid,  193 
Vanadium,  193 
Varieties  of  madder,  334 

of  red  liquor,  145 

of  sulphate  of  iron,  155 
Vat,  blue,  how  made,  288 
Vats,  288,  291,  293,  294,  297,  300,  302, 
305 

management  of,  302 
Vegetable  alkali,  113 
dyes,  new,  355 

fibres,  mordants  for  coal-tar  colors, 
395 

fibres,  no  affinity  for  coal-tar  co- 
lors, 390 

matters  used  in  dyeing,  234  1 

substances,  elements  of,  234 
Vegetables,  gallic  acid  not  found  largely 
in,  243 

oxygen  in,  47 
Venetian  sumach,  322 
Verdigris,  169 
Verona  sumach,  250 
Vert  lumiere,  383 
Victoria  orange,  382 
Vinegar,  composition  of,  236 

to  make  white  lead,  171 
sugar  of  lead,  171 
Violaniline,  379 
Violets,  aniline,  381 

soluble,  389 
Viol  &  Duflot,  feather  bleaching,  396 
Virey  on  carajuru,  358 
Vitality  affects  the  color,  240 
Vitriol,  blue,  168 

green,  152 

white,  165 
Vogei's  dye,  382 


422 


INDEX. 


\ 


Walnut  for  dyeing,  259 

Warrington's  method  of  ascertaining 

quantity  of  tannin,  259 
Water,  50 

action  on  indigo,  277 

as  a  solvent,  55 

oxygen  in,  47 

quality  of  affects  dyeing,  247 
required  to  dissolve  green  vitriol, 

153 
tests  for,  53 
Weight  of  silk  increased  by  dyeing, 
395 

Weissgerber's  experiments  with  oil, 

358 
Weld,  326 

White  copperas,  165 
indigo,  264,  277 
lead,  171 

oxide  of  arsenic,  197 
pattern  on  blue  ground,  282 
vitriol,  165 

Wild  cochineal,  366 

Williams,  discovery  of  fast  green,  &c, 
327 

Woad  plant,  260 

vat,  297 

and  pastel,  292 
Wold,  326 
Wolfram,  194 
Wongshy,  359 

colors  from,  362 

dyeing  with,  261 

reactions  with,  360,  361 

Stein  on,  359 

value  as  a  color,  361 
Woods,  314 

extracts  of,  326 

red,  314,  320 


Wood  vinegar  with  lead,  172 
yellow,  321 

Woody  fibre,  composition  of,  235 

Wool,  212 

aniline  black  on,  396 
dyeing  with  purpurine,  346 

Woollens,  mordant  for,  228 

Wools,  tests  for,  213 

Xanthin,  337 
Xanthine,  344 
Xantho-rhamnine,  328 

Yellow  chromate  of  potash,  187 
chrome,  189 

from  acetate  of  lead,  172 
from  lead,  171 
from  naphthaline,  387 
madder,  339 
Manchester,  387 
Martius',  387 
naphthylamine,  387 
Perkins', 

prussiate  of  potash,  119 

spirits,  183,  226 

wood,  321 
Yellows,  aniline,  382 
Young  fustic,  322 

Zinaline,  382 
Zinc,  164 

oxide  of,  165 

chloride  of,  165 

detected  in  copperas,  156 

nitrate  of,  165 

salts  of,  165 

salts,  precipitates  for,  1 65 
salts,  reactions  of,  165 
sulphate  of,  165 


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HENRY  CAREY  B AIRE'S  CATALOGUE 


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Edition,  with  Additions  by  John  Scoffern,  M.  B  ,  William  Clay, 
Wm.  Fairbairn,  F.  R.  S.,  and  James  Napier.  With  Five  Hun- 
dred and  Ninety-two  Engravings ;  Illustrating  every  Branch 
of  the  Subject.    In  one  volume,  8vo.    652  pages     .    $7  00 

DYRNE.— THE  PRACTICAL  MODEL  CALCULATOR: 

For  the  Engineer,  Mechanic,  Manufacturer  of  Engine  Work, 
Naval  Architect,  Miner,  and  Millwright.  By  Oliver  Byrne. 
1  volume,  8vo.,  nearly  600  pages      .       .       .       .    $4  50 

JgEMRO SE. — MANUAL  OF  WOOD  CARVINGr :  With  Practical  Il- 
lustrations for  Learners  of  the  Art,  and  Original  and  Selected  de- 
signs. By  William  Bemrose,  Jr.  With  an  Introduction  by 
Llewellyn  Jewitt,  F.  S.  A.,  etc.  With  128  Illustrations.  4to.? 
cloth  $3  00 


S  HENRY  CAREY  BAIRD'S  CATALOGUE. 

"DAIRD. — PROTECTION  OF  HOME  LABOR  AND  HOME  PRO- 
■°   SUCTIONS  NECESSARY  TO  THE  PROSPERITY  OF  THE 
AMERICAN  FARMER : 

By  Henry  Carey  Baird.    8vo.,  paper     .       *  10 


B 


B 


AIRD. — THE  RIGHTS  OF  AMERICAN  PRODUCERS,  AND  THE 
WRONGS  OF  BRITISH  FREE  TRADE  REVENUE  REFORM. 

By  Henry  Carey  Baird.    (1870)  ....  5 

AIRD.— SOME  OF  THE  FALLACIES  OF  BRITISH-FREE-TRADE 
REVENUE-REFORM. 

Two  Letters  to  Prof.  A.  L.  Perry,  of  Williams  College,  Mass.  By 
Henry  Carey  Baird.    (1871.)    Paper    ....  5 


B 


]g AIRD . — STANDARD  WAGES  COMPUTING  TABLES  : 

An  Improvement  in  all  former  Methods  of  Computation,  so  ar- 
ranged that  wages  for  days,  hours,  or  fractions  of  hours,  at  a  spe- 
cified rate  per  day  or  hour,  may  be  ascertained  at  a  glance.  By 
T.  Spangler  Baird.    Oblong  folio  $5  00 

AUERMAN. — TREATISE  ON  THE  METALLURGY  OF  IRON. 

Illustrated.    12mo   $2  50 

DICKNELL'.S  VILLAGE  BUILDER. 

*°    55  large  plates.    4to   $10  00 

BISHOP.— A  HISTORY  OF  AMERICAN  MANUFACTURES : 

From  1608  to  1866  ;  exhibiting  the  Origin  and  Growth  of  the  Prin- 
cipal Mechanic  Arts  and  Manufactures,  from  the  Earliest  Colonial 
Period  to  the  Present  Time  ;  By  J.  Leander  Bishop,  M.  D.,  Ed- 
ward Young,  and  Edwin  T.  Freedley.    Three  vols.  8vo., 

$10  00 

OX.— A  PRACTICAL  TREATISE  ON  HEAT  AS  APPLIED  TO 
THE  USEFUL  ARTS : 

For  the  use  of  Engineers,  Architects,  etc.  By  Thomas  Box,  au- 
thor of  "  Practical  Hydraulics."  Illustrated  by  14  plates,  con- 
taining 114  figures.    12mo  $4  25 


B 


QABINET  MAKER'S  ALBUM  OF  FURNITURE  : 

Comprising  a  Collection  of  Designs  for  the  Newest  and  Most 
Elegant  Styles  of  Furniture.  Illustrated  by  Forty-eight  Large 
and  Beautifully  Engraved  Plates.    In  one  volume,  oblong 

$5  00 

QHAPMAN.— A  TREATISE  ON  ROPE-MAKING  : 

As  practised  in  private  and  public  Rope-yards,  with  a  Description 
of  the  Manufacture,  Rules,  Tables  of  Weights,  etc.,  adapted  to  the 
Trade  ;  Shipping,  Mining,  Railways,  Builders,  etc.  By  Robert 
Chapman.    24mo,    .       .       .       .       ■.       -       .       ~    $1  50 


\ 


HENRY  CAREY  BAIRD'S  CATALOGUE. 


7 


pRAIK.— THE  PRACTICAL  AMERICAN  MILLWRIGHT  AND 
U  MILLER. 

Comprising  the  Elementary  Principles  of  Mechanics,  Me- 
chanism, and  Motive  Power,  Hydraulics  and  Hydraulic 
Motors,  Mill-dams,  Saw  Mills,  Grist  Mills,  the  Oat  Meal  Mill, 
the  Barley  Mill,  Wool  Carding,  and  Cloth  Fulling  and  Dress- 
ing, Wind  Mills,  Steam  Power,  &c.  By  David  Craik,  Mill' 
wright.  Illustrated  by  numerous  wood  engravings,  and  five 
folding  plates.    1  vol.  8vo.  „       .       .       .    $5  00 

HAMPIN. — A  PRACTICAL  TREATISE  ON  MECHANICAL  EN- 
U  GINEERING: 

Comprising  Metallurgy,  Moulding,  Casting,  Forging,  Tools, 
Workshop  Machinery,  Mechanical  Manipulation,  Manufacture 
of  Steam-engines,  etc.  etc.  With  an  Appendix  on  the  Ann- 
lysis  of  Iron  and  Iron  Ores.  By  Fbancis  Campin,  C.  E.  To 
which  are  added,  Observations  on  the  Construction  of  Steam 
Boilers,  and  Remarks  upon  Furnaces  used  for  Smoke  Preven- 
tion; with  a  Chapter  on  Explosions.  By  R.  Armstrong,  C.  E.s 
and  John  Bourne.  Rules  for  Calculating  the  Change  Wheels 
for  Screws  on  a  Turning  Lathe,  and  for  a  Wheel-cutting 
Machine.  By  J.  La  Nicca.  Management  of  Steel,  including 
Forging,  Hardening,  Tempering,  Annealing,  Shrinking,  anc( 
Expansion.  And  the  Case-hardening  of  Iron.  By  G.  Ede. 
8vo.   Illustrated  with  29  plates  and  100  wood  engravings. 

$6  00 

rt  AMP  IN. —THE  PRACTICE  OF  HAND-TURNING  IN  WOOD, 
U    IVORY,  SHELL,  ETC.  i 

With  Instructions  for  Turning  such  works  in  Metal  as  maybe 
required  in  the  Practice  of  Turning  Wood,  Ivory,  etc.  Also 
an  Appendix  on  Ornamental  Turning.  By  Francis  Campin  , 
with  Numerous  Illustrations,  12mo.,  cloth        .       .    $3  00 

pAPRON  DE  DOLE, — DITSSAUCE. — BLUES  AND  CARMINES  OF 
U  INDIGOc 

A  Practical  Treatise  on  the  Fabrication  of  every  Commercial 
Product  derived  from  Indigo.  By  Felicien  Capron  de  Dole 
Translated,  with  important  additions,  by  Professor  H.  Dc$» 
sauce.  12mo. 


HENRY  CAREY  BAIRDS  CATALOGUE. 

IAREY. — THE  WORKS  OF  HENRY  C>  CAREY : 

CONTRACTION  OR  EXPANSION  t  REPUDIATION  OR  RE- 
SUMPTION? Letters  to  Hon.  Hugh  McCulloch.    8yo.  38 
FINANCIAL  CRISES,  their  Causes  and  Effects.    8vo.  paper 

25 

HARMONY  OF  INTERESTS;   Agricultural,  Manufacturing, 

and  Commercial.    8vo.r  paper  $1  00 

Do.  do.  cloth        .       .       .    $1  50 

LETTERS  TO  THE  PRESIDENT  OF  THE  UNITED  STATES. 
Paper  $1  00 

MANUAL  OF  SOCIAL  SCIENCE.  Condensed  from  Carey's 
"  Principles  of  Social  Science/*  By  Kate  McKean.  1  vol. 
12mo   .       .    $2  25 

MISCELLANEOUS  WORKS:  comprising  "Harmony  of  Inter- 
ests," " Money,"1  "Letters  to  the  President,"  "French  and 
American  Tariffs,"  "Financial  Crises,"  "The  Way  to  Outdo 
England  without  Fighting  Her,"  " Resources  of  the  Union," 
"The  Public  Debt,"  "Contraction  or  Expansion,"  "Review 
of  the  Decade  1857 — '67,"  "Reconstruction,"  etc.  etc.  1  vol. 


8vo.,  cloth   .    $4  50 

MONEY:  A  LECTURE  before  the  N.  Y.  Geographical  and  Sta- 
tistical Society.    8vo.,  paper  25 

PAST,  PRESENT,  AND  FUTURE.    8vo.  .       .       .    $2  50 


PRINCIPLES  OF  SOCIAL  SCIENCE.    3  volumes  8vo.;  cloth 

$10  00 

REVIEW  OF  THE  DECADE  1857— '67.    8vo.,  paper  50 
RECONSTRUCTION :  INDUSTRIAL,  FINANCIAL,  AND  PO- 
LITICAL.   Letters  to  the  Hon.  Henry  Wilson,  U.  S.  S.  8vo 
paper      .......  .  50 

THE  PUBLIC  DEBT,  LOCAL  AND  NATIONAL.  How  to 
provide  for  its  discharge  while  lessening  the  burden  of  Taxa- 
tion. Letter  to  David  A.  Wells,  Esq.,  U.  S.  Revenue  Commis- 
sion.   8vo.,  paper    .......  25 

THE  RESOURCES  OF  THE  UNION.  A  Lecture  read,  Dec. 
1865,  before  the  American  Geographical  and  Statistical  So- 
ciety, N.  Y.,  and  before  the  American  Association  for  the-  Ad- 
vancement of  Social  Science,  Boston        ...  50 

THE  SLAVE  TRADE,  DOMESTIC  AND  FOREIGN;  Why  it 
Exists,  and  How  it  may  be  Extinguished.  12mo.,  cloth   $1  50 


HENRY  CAREY  BAIRD'S  CATALOGUE. 


9 


LETTERS    ON  INTERNATIONAL  COPYRIGHT.  (1867.) 

Paper  •  50 

KEVIEW  OF  THE  FARMERS'  QUESTION.  (1870.)  Paper  25 

RESUMPTION!  HOW  IT  MAY  PROFITABLY  BE  BROUGHT 
AROUT.    (1869.)    8vo.,  paper       ....  50 

REVIEW  OF  THE  REPORT  OF  HON.  D.  A.  WELLS,  Special 
Commissioner  of  the  Revenue.    (1869.)    8vo.,  paper  50 

SHALL  WE  HAVE  PEACE?  Peace  Financial  and  Peace  Poli- 
tical. Letters  to  the  President  Elect.  (1868.)  8vo.,  paper  50 

THE  FINANCE  MINISTER  AND  THE  CURRENCY,  AND 
THE  PUBLIC  DEBT.    (1868.)    8vo.,  paper  .       .  50 

THE  WAY  TO  OUTDO  ENGLAND  WITHOUT  FIGHTING 
HER.  Letters  to  Hon.  Schuyler  Colfax.  (1865.)  8vo.,  paper 

$1  00 

WEALTH!  OF  WHAT  DOES  IT  CONSIST  ?  (1870.)  Paper  25 

HAMUS.— A  TREATISE  ON  THE  TEETH  OF  WHEELS : 

Demonstrating  the  best  forms  which  can  be  given  to  them  for  the 
purposes  of  Machinery,  such  as  Mill-work  and  Clock-work.  Trans- 
lated from  the  French  of  M.  Camus.  By  John  I.  Hawkins. 
Illustrated  by  40  plates.    8vo  $3  00 

pIOXE. — MINING  LEGISLATION. 

A  paper  read  before  the  Am.  Social  Science  Association.  By 
Eckley  B.  Coxe.   Paper  20 

p 0LBTJRN . — THE  GAS-WORKS  OF  LONDON: 

Comprising  a  sketch  of  the  Gas-works  of  the  city,  Process  of 
Manufacture,  Quantity  Produced,  Cost,  Profit,  etc.  By  Zerah 
Colburn.    8vo.,  cloth  75 

H0LBTJRN. — THE  LOCOMOTIVE  ENGINE : 

Including  a  Description  of  its  Structure,  Rules  for  Estimat- 
ing its  Capabilities,  and  Practical  Observations  on  its  Construc- 
tion and  Management.  By  Zerah  Colburn.  Illustrated.  A 
new  edition.    12mo.  $1  25 

riOLBURN  AND  MAW. — THE  WATER-WORKS  OF  LONDON: 
Together  with  a  Series  of  Articles  on  various  other  Water- 
works.   By  Zerah  Colburn  and  W.  Maw.    Reprinted  front 
"  Engineering."    In  one  volume,  8vo.      .  .    $4  00 

nAGTJERREOTYPIST  AND  PHOTOGRAPHER'S  COMPANION: 

JJ    12mo.7  cloth  $1  25 


10 


HENRY  CAREY  BAIRD'S  CATALOGUE. 


"HIRCKS.— PERPETUAL  MOTION : 

Or  Search  for  Self-Motive  Power  during  the  17th,  18th,  and 
19th  centuries.  Illustrated  from  various  authentic  sources  in 
Papers,  Essays,  Letters,  Paragraphs,  and  numerous  Patent 
Specifications,  with  an  Introductory  Essay  by  Henry  Dircks, 
C.  E.  Illustrated  by  numerous  engravings  of  machines. 
12mo.,  cloth  $3  50 

TJIXON. — THE  PRACTICAL  MILLWRIGHT'S  AND  ENGINEER'S 
■U    GUIDE : 

Or  Tables  for  Finding  the  Diameter  and  Power  of  Cogwheels  ; 
Diameter,  Weight,  and  Power  of  Shafts ;  Diameter  and  Strength 
of  Bolts,  etc.  etc.   By  Thomas  Dixon.  12mo.,  cloth.    $1  50 

JJUNCAN. — PRACTICAL  SURVEYOR'S  GUIDE: 

Containing  the  necessary  information  to  make  any  person,  of 
common  capacity,  a  finished  land  surveyor  without  the  aid  of 
a  teacher.    By  Andrew  Duncan.   Illustrated.   12mo.,  cloth. 

$1  25 

"nUSSAUCE.— A  NEW  AND  COMPLETE  TREATISE  ON  THE 
13    ARTS  OF  TANNING,  CURRYING,  AND  LEATHER  DRESS- 
ING: 

Comprising  all  the  Discoveries  and  Improvements  made  in 
France,  Great  Britain,  and  the  United  States.  Edited  from 
Notes  and  Documents  of  Messrs.  Sallerou,  Grouvelle,  Duval, 
Dessables,  Labarraque,  Payen,  Rene\  De  Fontenelle,  Mala- 
peyre,  etc.  etc.    By  Prof.  H.  Dussauce,  Chemist.  Illustrated 

by  212  wood  engravings.    8vo  $10  00 

TjUSSAUCE. — A  GENERAL  TREATISE  ON  THE  MANUFACTURE 
OF  SOAP,  THEORETICAL  AND  PRACTICAL : 
Comprising  the  Chemistry  of  the  Art,  a  Description  of  all  the  Raw 
Materials  and  their  Uses.  Directions  for  the  Establishment  of  a 
Soap  Factory,  with  the  necessary  Apparatus,  Instructions  in  the 
Manufacture  of  every  variety  of  Soap,  the  Assay  and  Determination 
of  the  Value  of  Alkalies,  Fatty  Substances,  Soaps,  etc.  etc.  By 
Professor  H.  Dussauce.  With  an  Appendix,  containing  Ex- 
tracts from  the  Reports  of  the  International  Jury  on  Soaps,  as 
exhibited  in  the  Paris  Universal  Exposition,  1867,  numerous 
Tables,  etc.  etc.    Illustrated  by  engravings.    In  one  volume  8vo. 

of  over  800  pages     .       .  $10  00 

,USSAUCE.— PRACTICAL  TREATISE  ON  THE  FABRICATION 
OF  MATCHES,  GUN  COTTON,  AND  FULMINATING  POW- 
DERS. 

By  Professor  H.  Dussauce.    12mo.         .       .       .    $3  00 


D 


HENRY  CAREY  BAIRD'S  CATALOGUE. 


11 


TJUSSAUCE. — A  PRACTICAL  GUIDE  FOR  THE  PERFUMER : 

Being  a  New  Treatise  on  Perfumery  the  most  favorable  to  the 
Beauty  without  being  injurious  to  the  Health,  comprising  a 
Description  of  the  substances  used  in  Perfumery,  the  Form- 
ulae of  more  than  one  thousand  Preparations,  such  as  Cosme- 
tics, Perfumed  Oils,  Tooth  Powders,  Waters,  Extracts,  Tinc- 
tures, Infusions,  Vinaigres,  Essential  Oils,  Pastels,  Creams, 
Soaps,  and  many  new  Hygienic  Products  not  hitherto  described. 
Edited  from  Notes  and  Documents  of  Messrs.  Debay,  Lunel, 
etc.  With  additions  by  Professor  H.  Dussauce,  Chemist.  12mo. 

$3  00 

TYUSSAUCE. — A  GENERAL  TREATISE  ON  THE  MANUFACTURE 
-L'    OF  VINEGAR,  THEORETICAL  AND  PRACTICAL. 

Comprising  the  various  methods,  by  the  slow  and  the  quick  pro- 
cesses, with  Alcohol,  Wine,  Grain,  Cider,  and  Molasses,  as  weft 
as  the  Fabrication  of  Wood  Vinegar,  etc.  By  Prof.  H.  Dussauce. 
12mo.  $5  00 

TYUPLAIS. — A  COMPLETE  TREATISE  ON  THE  DISTILLATION 
U   AND  MANUFACTURE  OF  ALCOHOLIC  LIQUORS : 

From  the  French  of  M.  Duplais.  Translated  and  Edited  by  M. 
McKennie,  M  D.  Illustrated  by  numerous  large  plates  and  wood 
engravings  of  the  best  apparatus  calculated  for  producing  the 
finest  products.    In  one  vol.  royal  8vo.  $10  00 

This  is  a  treatise  of  the  highest  scientific  merit  and  of  the 
greatest  practical  value,  surpassing  in  these  respects,  as  well  as 
in  the  variety  of  its  contents,  any  similar  volume  in  the  English 
language. 

[YE  GRAFF.— THE  GEOMETRICAL  STAIR-BUILDERS'  GUIDE: 

Being  a  Plain  Practical  System  of  Hand-Railing,  embracing  all 
its  necessary  Details,  and  Geometrically  Illustrated  by  22  Steel 
Engravings  ;  together  with  the  use  of  the  most  approved  princi- 
ples of  Practical  Geometry.    By  Simon  De  Graff,  Architect. 

4to.         .  $5  00 

TjYER  AND  COLOR-MAKER'S  COMPANION  : 

Containing  upwards  of  two  hundred  Receipts  for  making  Co- 
lors, on  the  most  approved  principles,  for  all  the  various  styles 
and  fabrics  now  in  existence  ;  with  the  Scouring  Process,  and 
plain  Directions  for  Preparing,  Washing-off,  and  Finishing  the 
Oroods.    In  one  vol.  12mo  $1  25 


12  HENRY  OaRBY  BAIRD'S  CATALOGUE. 


1?  AST  ON. — A  PKACTICAL  TREATISE  ON  STREET  OR  HORSE- 
POWER  RAILWAYS : 

Their  Location,  Construction,  and  Management ;  with  General 
Plans  and  Rules  for  their  Organization  and  Operation ;  toge- 
ther with  Examinations  as  to  their  Comparative  Advantages 
over  the  Omnibus  System,  and  Inquiries  as  to  their  Value  for 
Investment;  including  Copies  of  Municipal  Ordinances  relat- 
ing thereto.  By  Alexander  Easton,  C.  E.  Illustrated  by  23 
plates,  8vo.,  cloth    .  $2  00 

pSRSYTH. — BOOK  OF  DESIGNS  FOR  HEAB-STONES,  MURAL, 
C     AND  OTHER  MONUMENTS  : 

Containing  78  Elaborate  and  Exquisite  Designs.    By  Forsyth. 

4to.,  cloth        .       .  /    .  $5  00 

This  volume,  for  the  beauty  and  variety  of  its  designs,  has 
never  been  surpassed  by  any  publication  of  the  kind,  and  should 
be  in  the  hands  of  every  marble-worker  who  does  fine  monumental 
work. 

pAIRBAIRN.— THE  PRINCIPLES  OF  MECHANISM  AND  MA- 
X     CHINERY  OF  TRANSMISSION : 

Comprising  the  Principles  of  Mechanism,  Wheels,  and  Pulleys, 
Strength  and  Proportions  of  Shafts,  Couplings  of  Shafts,  and 
Engaging  and  Disengaging  Gear.  By  William  Fairbairn, 
Esq.,  C.  E.,  LL.  D.,  F.  R.  S.,  F.  G.  S.,  Corresponding  Member 
of  the  National  Institute  of  France,  and  of  the  Royal  Academy 
of  Turin  ;  Chevalier  of  the  Legion  of  Honor,  etc.  etc.  Beau- 
tifully illustrated  by  over  150  wood-cuts.  In  one  volume  12mo. 

$2  50 

pAIRBAIRN.— PRIME-MOVERS : 

Comprising  the  Accumulation  of  Water-power ;  the  Construc- 
tion of  Water-wheels  and  Turbines;  the  Properties  of  Steam; 
the  Varieties  of  Steam-engines  and  Boilers  and  Wind-mills. 
By  William  Fairbairn,  C.  E.,  LL.  D.,  F.  R.  S.,  F.  G.  S.  Au- 
thor of  "  Principles  of  Mechanism  and  the  Machinery  of  Trans- 
mission. "  With  Numerous  Illustrations.  In  one  volume.  (In 
press.) 

piLBART. — A  PRACTICAL  TREATISE  ON  BANKING: 

^    By  James  William  Gilbart.    To  which  is  added:  The  Na- 
tional Bank  Act  as  now  in  force.    8vo.       .       .$4  5® 

HESNER. — A  PRACTICAL  TREATISE  ON  COAL,  PETROLEUM, 
^    AND  OTHER  DISTILLED  OILS. 

By  Abraham  Gesner,  M.  D.,  F.  G.  S.  Second  edition,  revised 
and  enlarged.  By  George  Weltden  Gesner,  Consulting 
Chemist  and  Engineer.    Illustrated.    8vo.     •       .    $3  50 


HENRY  CAREY  BAIRNS  CATALOGUE, 


nOTHIC  ALBUM  FOR  CABINET  MAKERS: 

Comprising  a  Collection  of  Designs  for  Gothic  Furniture.  Ii< 
lustrated  by  twenty-three  large  and  beautifully  engraved 
plates.    Oblong  $3  00 

H  RANT. — BEET-ROOT  SUGAR  AND  CULTIVATION  OF  THE 
^    BEET : 

By  E.  B.  Grant.    12mo.        .       .  ■     .       .       .    $1  25 

H  REGORY. — MATHEMATICS  FOR  PRACTICAL  MEN  : 

Adapted  to  the  Pursuits  of  Surveyors,  Architects,  Mechanics, 
and  Civil  Engineers.  By  Olinthus  Gregory.  8vo.,  plates, 
cloth  $3  00 

HRISWOLD. — RAILROAD  ENGINEER'S  POCKET  COMPANION. 

Comprising  Rules  for  Calculating  Deflection  Distances  and 
Angles,  Tangential  Distances  and  Angles,  and  all  Necessary 
Tables  for  Engineers ;  also  the  art  of  Levelling  from  Prelimi- 
nary Survey  to  the  Construction  of  Railroads,  intended  Ex- 
pressly for  the  Young  Engineer,  together  with  Numerous  Valu- 
able Rules  and  Examples.    By  W.  Griswold.    12mo.,  tucks. 

$1  75 

H  UETTIER. — METALLIC  ALLOYS  : 

Being  a  Practical  Guide  to  their  Chemical  and  Physical  Pro- 
perties, their  Preparation,  Composition,  and  Uses.  Translated 
from  the  French  of  A.  Guettier,  Engineer  and  Director  of 
Founderies,  author  of  ' '  La  Fouderie  en  France,"  etc.  etc.  By 
A.  A.  Fesquet,  Chemist  and  Engineer,  In  one  volume,  12mo. 

$3  00 

TTATS  AND  FELTING: 

A  Practical  Treatise  on  their  Manufacture.    By  a  Practical 

Hatter.    Illustrated  by  Drawings  of  Machinery,  &c,  8vo. 

$1  2k 

XT  AY. — THE  INTERIOR  DECORATOR: 

The  Laws  of  Harmonious  Coloring  adapted  to  Interior  Decora- 
tions :  with  a  Practical  Treatise  on  House-Painting.  By  D. 
R.  Hat,  House-Painter  and  Decorator.  Illustrated  by  a  Dia- 
gram of  the  Primary,  Secondary,  and  Tertiary  Colors.  12mo. 

$2  25 

TTUGHES.— AMERICAN  MILLER  AND  MILLWRIGHT'S  AS- 
11    SI  ST  ANT : 

By  Wm.  Carter  Hughes.  A  new  edition.  In  one  volume, 
12mo.     .       .       .       .  .       ...    $1  50 


14  HENRY  CAREY  BAIRD'S  CATALOGUE. 


JJUNT. — THE  PRACTICE  OF  PHOTOGRAPHY. 

By  Robert  Hunt,  Vice-President  of  the  Photographic  Society, 
London.  With  numerous  illustrations.   12mo.,  cloth  .  75 


RST.— A  HAND-BOOK  FOR  ARCHITECTURAL  SURVEYORS  r 

Comprising  Formulse  useful  in  Designing  Builders'  work,  Table 
of  Weights,  of  the  materials  used  in  Building,  Memoranda 
connected  with  Builders'  work,  Mensuration,  the  Practice  of 
Builders'  Measurement,  Contracts  of  Labor,  Valuation  of  Pro- 
perty, Summary  of  the  Practice  in  Dilapidation,  etc.  etc.  By 
J.  F.  Hurst,  C.  E.    2d  edition,  pocket-book  form,  full  bound 

$2  50 


!RVIS. — RAILWAY  PROPERTY: 

A  Treatise  on  the  Construction  and  Management  of  Railways ; 
designed  to  aiford  useful  knowledge,  in  the  popular  style,  to  the 
holders  of  this  class  of  property  as  well  as  Railway  Mana- 
gers, Officers,  and  Agents.  By  John  B.  Jervis,  late  Chief 
Engineer  of  the  Hudson  River  Railroad,  Croton  Aqueduct^  &c. 
One  vol.  12mo.,  cloth       .  .    $2  00 


'OHNSON. — A  REPORT  TO  THE  NAVY  DEPARTMENT  OF  THE 
UNITED  STATES  ON  AMERICAN  COALS : 

Applicable  to  Steam  Navigation  and  to  other  purposes.  By 
Walter  R.  Johnson.  With  numerous  illustrations.  607  pp. 
8vo.,,  .  ...  $10  00 


0HNST0N.— INSTRUCTIONS  FOR  THE  ANALYSIS  OF  SOILS, 
LIMESTONES,  AND  MANURES 

By  J.  W.  F.  Johnston.    12mo.        .  35 


gTSENE. — A  HAND-BOOK  OF  PRACTICAL  GAUGING, 

For  the  Use  of  Beginners,  to  which  is  added  a  Chapter  on  Dis- 
tillation, describing  the  process  in  operation  at  the  Custom 
House  for  ascertaining  the  strength  of  wines.  By  James  B. 
Keene,  of  H.  M.  Customs.    8vo,     .  .   $1  25 


HENRY  CAREY  BAIRD'S  CATALOGUE. 


gENTISH.— A  TREATISE  ON  A  BOX  OF  INSTRUMENTS,  ' 


And  the  Slide  Rule  ;  with  the  Theory  of  Trigonometry  and  Lo-  y 
garithms,  including  Practical  Geometry,  Surveying,  Measur- 
ing of  Timber,  Cask  and  Malt  Gauging,  Heights,  and  Distances. 
By  Thomas  Kentish.    In  one  volume.    12mo.  .       .    $1  25 


OBELL.—ERNL— MINERALOGY  SIMPLIFIED : 

A  short  method  of  Determining  and  Classifying  Minerals,  by 
means  of  simple  Chemical  Experiments  in  the  Wet  Way. 
Translated  from  the  last  German  Edition  of  F.  Von  Kobell, 
with  an  Introduction  to  Blowpipe  Analysis  and  other  addi- 
tions. By  Henri  Erni,  M.  D.,  Chief  Chemist,  Department  of 
Agriculture,  author  of  "Coal  Oil  and  Petroleum."  In  one 
volume.    12mo.       .  .  $2  50 


ANDRIN. — A  TREATISE  ON  STEEL: 

Comprising  its  Theory,  Metallurgy,  Properties,  Practical  Work- 
ing, and  Use.  By  M.  H.  C.  Landrin,  Jr.,  Civil  Engineer. 
Translated  from  the  French,  with  Notes,  by  A.  A.  Fesquet, 
Chemist  and  Engineer.  With  an  Appendix  on  the  Bessemer 
and  the  Martin  Processes  for  Manufacturing  Steel,  from  the 
Report  of  Abram  S.  Hewitt,  United  States  Commissioner  to 
the  Universal  Exposition,  Paris,  1867.    12mo.  .       .    $3  00 


ARKIN. — THE  PRACTICAL  BRASS  AND  IRON  FOUNDER'S 
1  GUIDE. 

A  Concise  Treatise  on  Brass  Founding,  Moulding,  the  Metals 
and  their  Alloys,  etc. ;  to  which  are  added  Recent  Improve- 
ments in  the  Manufacture  of  Iron,  Steel  by  the  Bessemer  Pro- 
cess, etc.  etc.  By  James  Larkin,  late  Conductor  of  the  Brass 
Foundry  Department  in  Reany,  Neafie  &  Co.'s  Penn  Works, 
Philadelphia.  Fifth  edition,  revised,  with  extensive  Addi- 
tions.   Ia  one  volume.    12mo.  .       .  .       .    $2  25 


HENRY  CAREY  BAIRD'S  CATALOGUE. 


T  EAVITT. — FACTS  ABOUT  PEAT  AS  AN  ARTICLE  OF  FUEL? 

With  Remarks  upon  its  Origin  and  Composition,  the  Localities 
m  which  it  is  found,  the  Methods  of  Preparation  and  Manu 
facture,  and  the  various  Uses  to  which  it  is  applicable ;  toge 
ther  with  many  other  matters  of  Practical  and  Scientific  Inte- 
rest. To  which  is  added  a  chapter  on  the  Utilization  of  Coal 
Dust  with  Peat  for  the  Production  of  an  Excellent  Fuel  at 
Moderate  Cost,  especially  adapted  for  Steam  Service.  By  H. 
T.  Leavitt.    Third  edition.    12mo.         .       .       .    $1  75 

T  ER0UX= — A  PRACTICAL  TREATISE  ON  THE  MANUFAC- 
TURS  OF  WORSTEDS  AND  CARDED  YARNS: 
Translated  from  the  French  of  Charles  Leroux,  Mechanical 
Engineer,  and  Superintendent  of  a  Spinning  Mill.  By  Dr,  H. 
Paine,  and  A.  A.  Fesquet.  Illustrated  by  12  large  plates,  In 
one  volume  8vo.       .  $5  00 

TESLIE  (MISS) . — COMPLETE  COOKERY : 

Directions  for  Cookery  in  its  Various  Branches.  By  Miss 
Leslie.  60th  edition.  Thoroughly  revised,  with  the  addi- 
tion of  New  Receipts.    In  1  vol.  12mo.,  cloth  .       .    $1  50 

TESLIE  (MISS).  LADIES'  HOUSE  BOOK: 

a  Manual  of  Domestic  Economy.  20th  revised  edition.  12mo., 
cloth        .       .       .  $1  25 

TESLIE  (MISS)  .—TWO  HUNDRED  RECEIPTS  IK  FRENCH 
Jj  COOKERY. 

12mo  50 

T  IEBER. — ASSAYER'S  GUIDE : 

Or,  Practical  Directions  to  Assayers,  Miners,  and  Smelters,  for 
the  Tests  and  Assays,  by  Heat  and  by  Wet  Processes,  for  the 
Ores  of  all  the  principal  Metals,  of  Gold  and  Silver  Coins  and 
Alloys,  and  of  Coal,  etc.  By  Oscar  M.  Lieber.    12mo.,  cloth 

$1  25 

T  OVE. — THE  ART  OF  DYEING,  CLEANING,  SCOURING,  AND 
U    FINISHING ; 

On  the  most  approved  English  and  French  methods ;  being 
Practical  Instructions  in  Dyeing  Silks,  Woollens,,  and  Cottons, 
Feathers,  Chips,  Straw,  etc.;  Scouring  and  Cleaning  Bed  and 
Window  Curtains,  Carpets,  Rugs,  etc.;  French  and  English 
Cleaning,  etc.  By  Thomas  Love.  Second  American  Edition,  to 
which  are  added  General  Instructions  for  the  Use  of  Aniline 
Colors..    8vo..     r       .       .       .       „       *       •       „       ,    5  00 


HENRY  CAREY  BAIRD'S  CATALOGUE.  17 


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TWTAIN  AND  BROWN. — QUESTIONS  ON  SUBJECTS  CONNECTED 
1V1  WITH  THE  MARINE  STEAM-ENGINE : 

And  Examination  Papers  ;  with  Hints  for  their  Solution.  By 
Thomas  J.  Main,  Professor  of  Mathematics,  Royal  Naval  College, 
and  Thomas  Brown,  Chief  Engineer,  R.N.     12mo.,  cloth  $1  50 

AIN  AND  BROWN. — THE  INDICATOR  AND  DYNAMOMETER 

With  their  Practical  Applications  to  the  Steam-Engine.  By 
Thomas  J.  Main,  M.  A.  F.  R.,  Ass't  Prof.  Royal  Naval  College, 
Portsmouth,  and  Thomas  Brown,  Assoc.  Inst.  C.  E.,  Chief  En- 
gineer, R.  N.,  attached  to  the  R.  N.  College.  Illustrated.  From 
the  Fourth  London  Edition.    8vo.   ...  .    $1  50 

AIN  AND  BROWN  — THE  MARINE  STEAM-ENGINE. 

By  Thomas  J.  Main,  F.  R.  Ass't  S.  Mathematical  Professor  at 
Royal  Naval  College,  and  Thomas  Brown,  Assoc.  Inst.  C.  E. 
Chief  Engineer,  R.  N.     Attached  to  the  Royal  Naval  College. 
Authors  of  "  Questions  Connected  with  the  Marine  Steam-En- 
gine," and  the  '*  Indicator  and  Dynamometer."    With  numerous 
Illustrations.    In  one  volume  8vo.   .       .       .       .       .    $5  00 

ARIIN.— SCREW-CUTTING  TABLES,  FOR  THE  USE  OF  ME- 
CHANICAL ENGINEERS : 

Showing  the  Proper  Arrangement  of  Wheels  for  Cutting  the 
Threads  of  Screws  of  any  required  Pitch ;  with  a  Table  for 
Making  the  Universal  Gas-Pipe  Thread  and  Taps.    By  W.  A. 

Martin,  Engineer.    8vo  50 

ILES — A  PLAIN  TREATISE  ON  HORSE-SHOEING. 
With  Illustrations.   By  William  Miles,  author  of  "The  Horse's 
Foot" 

TUTOLES WORTH. — POCKET-BOOK  OF  USEFUL  FORMULAE  AND 
1YJ-  MEMORANDA  FOR  CIVIL  AND  MECHANICAL  EN3INEERS. 

By  Guilford  L.  Molesworth,  Member  of  the  Institution  of 
Civil  Engineers,  Chief  Resident  Engineer  of  the  Ceylon  Railway. 
Second  American  from  the  Tenth  London  Edition.  In  one 
volume,  full  bound  in  pocket-book  form  .       .        .       .    $2  0(1 

OORE.— THE  INVENTOR'S  GUIDE: 

Patent  Office  and  Patent  Laws  :  or,  a  Guide  to  Inventors,  and  a 
Book  of  Reference  for  Judges,  Lawyers,  Magistrates,  and  others. 

By  J  G.  Moore.    12mo.,  cloth  $1  25 

APIER. — A  MANUAL  OF  ELECTRO-METALLURGY : 
Including  the  Application  of  the  Art  to  Manufacturing  Processes. 
By  James  Napier.    Fourth  American,  from  the  Fourth  London 
edition,  revised  and  enlarged.    Illustrated  by  engravings.  In 
one  volume,  8vo  $2  00 


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18  HENRY  CAREY  BAIRD'S  CATALOGUE. 


"VTAPIER. — A  SYSTEM  OF  CHEMISTRY  APPLIED  TO  DYE  IN  ft : 

By  James  Napier,  F.  C.  S.  A  New  and  Thoroughly  Revised 
Edition,  completely  brought  up  to  the  present  state  of  the 
Science,  including  the  Chemistry  of  Coal  Tar  Colors.  By  A.  A. 
Fesquet, 'Chemist  and  Engineer.  With  an  Appendix  on  Dyeing 
and  Calico  Printing,  as  shown  at  the  Paris  Universal  Exposition 
of  1867,  from  the  Reports  of  the  International  Jury,  etc.  Illus- 
trated.   In  one  volume  8vo.,  400  pages    .       .       .       .    $5  00 

TVTEWBERY.  —  GLEANINGS   FROM    ORNAMENTAL   ART  OF 

^   EVERY  STYLE; 

Drawn  from  Examples  in  the  British,  South  Kensington,  Indian, 
Crystal  Palace,  and  other  Museums,  the  Exhibitions  of  1851  and 
1862,  and  the  best  English  and  Foreign  works.  In  a  series  of  one 
hundred  exquisitely  drawn  Plates,  containing  many  hundred  ex- 
amples.   By  Robert  Newbery.    4to  $15  00 

jy^ICHOLSON. — A  MANUAL  OF  THE  ART  OF  BOOK-BINDING : 

Containing  full  instructions  in  the  different  Branches  of  Forward- 
ing, Gilding,  and  Finishing.  Also,  the  Art  of  Marbling  Book- 
edges  and  Paper.  By  James  B.  Nicholson.  Illustrated.  12mo. 
cloth         ....  .....    $2  2i 

■VTORRIS.— A  HAND-BOOK  FOR  LOCOMOTIVE  ENGINEERS  AND 
1N  MACHINISTS: 

Comprising  the  Proportions  and  Calculations  for  Constructing 
Locomotives ;  Manner  of  Setting  Valves ;  Tables  of  Squares, 
Cubes,  Areas,  etc.  etc.  By  Septimus  Norris,  Civil  and  Me- 
chanical Engineer.    New  edition.    Illustrated,  12mo.,  cloth 

$2  00 

MYSTROM.  —  ON  TECHNOLOGICAL  EDUCATION  AND  THE 
r   CONSTRUCTION  OF  SHIPS  AND  SCREW  PROPELLERS: 

For  Naval  and  Marine  Engineers.  By  John  W.  Nystrom,  late 
Acting  Chief  Engineer  U.  S.  N.  Second  edition,  revised  with 
additional  matter.    Illustrated  by  seven  engravings.  12mo. 

$2  50 

NEILL. — A  DICTIONARY  OF  DYEING  AND  CALICO  PRINT- 
ING: 

Containing  a  brief  account  of  all  the  Substances  and  Processes  in 
use  in  the  Art  of  Dyeing  and  Printing  Textile  Fabrics  :  with  Prac- 
tical Receipts  and  Scientific  Information.  By  Charles  O'Neill, 
Analytical  Chemist ;  Fellow  of  the  Chemical  Society  of  London  ; 
Member  of  the  Literary  and  Philosophical  Society  of  Manchester  ; 
Author  of  "  Chemistry  of  Calico  Printing  and  Dyeing."  To  which 
is  added  An  Essay  on  Coal  Tar  Colors  and  their  Application  to 


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HENRY  CAREY  BAIRD'S  CATALOGUE. 


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Dyeing  and  Calico  Printing.  By  A.  A.  Fesquet,  Chemist  and 
Engineer.  With  an  Appendix  on  Dyeing  and  Calico  Printing,  as 
shown  at  the  Exposition  of  1867,  from  the  Reports  of  the  Interna, 
tional  Jury,  etc.  In  one  volume  8vo.,  491  pages  .  .  $6  00 
S BORN.— THE  METALLURGY  OF  IRON  AND  STEEL: 

Theoretical  and  Practical :  In  all  its  Branches  ;  With  Special  Re- 
ference to  American  Materials  and  Processes.  By  H.  S.  Osborn, 
LL.  D.,  Professor  of  Mining  and  Metallurgy  in  Lafayette  College, 
Easton,  Pa.    Illustrated  by  230  Engravings  on   Wood,  and  6 

Folding  Plates.    8vo.,  972  pages  $10  00 

QSBORN. — AMERICAN  MINES  AND  MINING  : 
v    Theoretically  and  Practically  Considered.    By  Prof.  H.  S.  Os- 
born, Illustrated  by  numerous  engravings.  8vo.  {hi  preparation.) 
pAINTER,  GILDER,  AND  VARNISHER'S  COMPANION : 

Containing  Rules  and  Regulations  in  everything  relating  to  the 
Arts  of  Painting,  Gilding,  Varnishing,  and  Glass  Staining,  with 
numerous  useful  and  valuable  Receipts;  Tests  for  the  Detection 
of  Adulterations  in  Oils  and  Colors,  and  a  statement  of  the  Dis- 
eases and  Accidents  to  which  Painters,  Gilders,  and  Varnishers 
are  particularly  liable,  with  the  simplest  methods  of  Prevention 
and  Remedy.  With  Directions  for  Graining,  Marbling,  Sign  Writ- 
ing, and  Gilding  on  Glass.  To  which  are  added  Complete  Instruc- 
tions for  Coach  Painting  and  Varnishing.   12mo.,  cloth,  $1  50 

pALLETT.  — THE  MILLER'S,  MILLWRIGHT'S,  AND  ENGI- 
L    NEER'S  GUIDE. 

By  Henry  Pallett.  Illustrated.  In  one  vol.  12mo.  .  $3  00 
pERKINS.— GAS  AND  VENTILATION. 

Practical  Treatise  on  Gas  and  Ventilation.  With  Special  Relation 
to  Illuminating,  Heating,  and  Cooking  by  Gas.  Including  Scien- 
tific Helps  to  Engineer-students  and  others.  With  illustrated 
Diagrams.    By  E.  E.  Perkins.    12mo.,  cloth  .       .       .    $1  25 

HEREIN  S  AND  ST  OWE. — A  NEW  GUIDE  TO  THE  SHEET-IRON 

L    AND  BOILER  PLATE  ROLLER : 

Containing  a  Series  of  Tables  showing  the  Weight  of  Slabs  and 
Piles  to  Produce  Boiler  Plates,  and  of  the  Weight  of  Piles  and  the 
Sizes  of  Bars  to  Produce  Sheet-iron  ;  the  Thickness  of  the  Bar 
Gauge  in  Decimals ;  the  Weight  per  foot,  and  the  Thickness  on 
the  Bar  or  Wire  Gauge  of  the  fractional  parts  of  an  inch ;  the 
Weight  per  sheet,  and  the  Thickness  on  the  Wire  Gauge  of  Sheet- 
iron  of  various  dimensions  to  weigh  112  lbs.  per  bundle  ;  and  the 
conversion  of  Short  Weight  into  Long  Weight,  and  Long  Weight 
into  Short.  Estimated  and  collected  by  G»  II.  Perkins  and  J.  G' 
Stowe   .       ,       ,    $2  50 


20 


HENRY  CAREY  BAIRD'S  CATALOGUE. 


pHILLIPS  AND  DARLINGTON.— RECORDS  OF  MINING  AND 
£    METALLURGY : 

Or,  Facts  and  Memoranda  for  the  use  of  the  Mine  Agent  and 
Smelter.  By  J.  Arthur  Phillips,  Mining  Engineer,  Graduate  of 
the  Imperial  School  of  Mines,  France,  etc.,  and  John  Darlington. 
Illustrated  by  numerous  engravings.  In  one  vol.  12mo.  .  $2  00 
pRADAL,  MALEPEYRE,  AND  DUS  SAUCE.  —  A  COMPLETE 
TREATISE  ON  PERFUMERY : 

Containing  notices  of  the  Raw  Material  used  in  the  Ait,  and  the 
Best  Formulae.  According  to  the  most  approved  Methods  followed 
in  France,  England,  and  the  United  States.  By  M.  P.  Pradal, 
Perfumer-Chemist,  and  M.  F.  Malepeyre.  Translated  from  the 
French,  with  extensive  additions,  by  Prof.  H.  Dussauce.  8vo.  $10 

pROTEAUX.— PRACTICAL  GUIDE  FOR  THE  MANUFACTURE 
X    OF  PAPER  AND  BOARDS. 

By  A.  Proteaux,  Civil  Engineer,  and  Graduate  of  the  School  of 
Arts  and  Manufactures,  Director  of  Thiers's  Paper  Mill,  7Puy-de- 
Dome.  With  additions,  by  L.  S.  Le  Normand.  Translated  from 
the  French,  with  Notes,  by  Horatio  Paine,  A.  B.,  M.  D.  To 
which  is  added  a  Chapter  on  the  Manufacture  of  Paper  from  Wood 
in  the  United  States,  by  Henry  T.  Brown,  of  the  "American 
Artisan."  Illustrated  by  six  plates,  containing  Drawings  of  Raw 
Materials,  Machinery,  Plans  of  Paper-Mills,  etc.  etc.  8vo.  $5  00 
TD EGNAULT. — ELEMENTS  OF  CHEMISTRY. 

By  M.  Y.  Regnault.  Translated  from  the  French  by  T.  For- 
rest Benton,  M.  Ik ,  and  edited,  with  notes,  by  James  C.  Booth, 
Melter  and  Refiner  U.  S.  Mint,  and  Wm.  L.  Faber,  Metallurgist 
and  Mining  Engineer.  Illustrated  by  nearly  700  wood  engravings » 
Comprising  nearly  1500  pages.    In  two  vols.  8vo.,  cloth    $10  00 

TDEID. — A  PRACTICAL  TREATISE  ON  THE  MANUFACTURE  OF 
11  PORTLAND  CEMENT: 

By  Henry  Reid,  C.  E.    To  which  is  added  a  Translation  of  M. 
A.  Lipowitz's  Work,  describing  a  new  method  adopted  in  Germany 
of  Manufacturing  that  Cement.    By  W.  F.  Rem.    Illustrated  by 
plates  and  wood  engravings.    8vo.  .       .       .       .       .    $7  00 

•DIFFAULT,  VERGNAUD,   AND  TOUSSAINT. — A  PRACTICAL 
11  TREATISE   ON  THE  MANUFACTURE   OF   COLORS  FOR 
PAINTING: 

Containing  the  best  Formulae  and  the  Processes  the  Newest  and 
in  most  General  Use.  By  MM.  Riffault,  Vergnaub,  and  Tous- 
saint.  Revised  and  Edited  by  M.  F.  Malepeyre  and  Dr.  Emil 
Winckler.  Illustrated  by  Engravings*  In  one  voL  Svo.  {In 
preparation^ 


HENRY  CAREY  BATRD'S  CATALOGUE. 


21 


DIFEAULT,  VERGrNAUD,  AND  TOUSSAINT.— A  PRACTICAL 
TREATISE  ON  THE  MANUFACTURE  OF  VARNISHES : 

By  MM.  Riffault,  Vergnaud,  and  Toussaint.  Revised  and 
Edited  by  M.  F.  Malepeyre  and  Dr.  Emil  Winckler.  Illus- 
trated.   In  one  vol.  8vo.    (hi  preparation.) 

OHUNK. — A  PRACTICAL  TREATISE  ON  RAILWAY  CURVES 
°    AND  LOCATION,  FOR  YOUNG  ENGINEERS. 

By  Wm.  F.  Shunk,  Civil  Engineer.    12mo.,  tucks   .       .    $2  00 

gMEATON.— BUILDER'S  POCKET  COMPANION: 

Containing  the  Elements  of  Building,  Surveying,  and  Architec. 
ture  ;  with  Practical  Rules  and  Instructions  connected  with  the  sub- 
ject. By  A.  C.  Smeaton,  Civil  Engineer,  etc.  In  one  volume, 
12mo.       .       .  $1  50 

HMITH.— THE  DYER'S  INSTRUCTOR: 

Comprising  Practical  Instructions  in  the  Art  of  Dyeing  Silk,  Cot- 
ton, Wool,  and  Worsted,  and  Woollen  Goods:  containing  nearly 
800  Receipts.  To  which  is  added  a  Treatise  on  the  Art  of  Pad- 
ding j  and  the  Printing  of  Silk  Warps,  Skeins,  and  Handkerchiefs, 
and  the  various  Mordants  and  Colors  for  the  different  styles  of 
such  work.    By  David  Smith,  Pattern  Dyer,  12mo.,  cloth 

$3  0& 

OMITH.— THE  PRACTICAL  DYER'S  GUIDE: 

Comprising  Practical  Instructions  in  the  Dyeing  of  Shot  Cobourgs, 
Silk  Striped  Orleans,  Colored  Orleans  from  Black  Warps,  ditto 
from  White  Warps,  Colored  Cobourgs  from  White  Warps,  Merinos, 
Yarns,  Woollen  Cloths,  etc.  Containing  nearly  300  Receipts,  to 
most  of  which  a  Dyed  Pattern  is  annexed.  Also,  a  Treatise  on 
the  Art  of  Padding.    By  David  Smith.    In  one  vol.  8vo.  $25  00 

OHAW. — CIVIL  ARCHITECTURE : 

Being  a  Complete  Theoretical  and  Practical  System  of  Building, 
containing  the  Fundamental  Principles  of  the  Art.  By  Edward 
Shaw,  Architect.  To  which  is  added  a  Treatise  on  Gothic  Archi- 
tecture, &c.  By  Thomas  W.  Silloway  and  George  M.  Hard- 
ing ,  Architects.  The  whole  illustrated  by  102  quarto  plates  finely 
engraved  on  copper.    Eleventh  Edition.    4to.    Cloth.       $10  00 

OLOAN. — AMERICAN  HOUSES : 

A  variety  of  Original  Designs  for  Rural  Buildings.  Illustrated  by 
26  colored  Engravings,  with  Descriptive  References.  By  Samuel 
Sloan,  Architect,  author  of  the  "  Model  Architect,"  etc.  etc.  8vo. 

$2  50 

OCHINZ.— RESEARCHES  ON  THE  ACTION  OF  THE  BLAST. 
D  FURNACE. 

By  Chas.  Schinz.    Seven  plates.    12mo.        .  .    $4  25 


\ 


22 


HENRY  CAREY  BAIRD'S  CATALOGUE. 


OMITH.— PARKS  AND  PLEASURE  GROUNDS : 

Or,  Practical  Notes  on  Country  Residences,  Villas,  Public  Parks, 
and  Gardens.  By  Charles  H.  J.  Smith,  Landscape  Gardener 
and  Garden  Architect,  etc.  etc.    12mo.   .       ,       .       .    $2  25 

OTOKES.— CABINET-MAKER'S  AND  UPHOLSTERER'S  COMPA- 
°  NION: 

Comprising  the  Rudiments  and  Principles  of  Cabinet-making  and 
Upholstery,  with  Familiar  Instructions,  Illustrated  by  Examples 
for  attaining  a  Proficiency  in  the  Art  of  Drawing,  as  applicable 
to  Cabinet-work  ;  The  Processes  of  Veneering,  Inlaying,  and 
Buhl-work  ;  the  Art  of  Dyeing  and  Staining  Wood,  Bone,  Tortoise 
Shell,  etc.  Directions  for  Lackering,  Japanning,  and  Varnishing; 
to  make  Prench  Polish  ;  to  prepare  the  Best  Glues,  Cements,  and 
Compositions,  and  a  number  of  Receipts,  particularly  for  workmen 
generally.    By  J.  Stokes.  In  one  vol.  12mo.    With  illustrations 

$1  25 

STRENGTH  AND  OTHER  PROPERTIES  OF  METALS. 

Reports  of  Experiments  on  the  Strength  and  other  Properties  of 
Metals  for  Cannon.  With  a  Description  of  the  Machines  for  Test- 
ing Metals,  and  of  the  Classification  of  Cannon  in  service.  By 
Officers  of  the  Ordnance  Department  U.  S.  Army.  By  authority 
of  the  Secretary  of  War.  Illustrated  by  25  large  steel  plates.  In 
1  vol.  quarto   .  .  $10  00 

SULLIVAN. — PROTECTION  TO  NATIVE  INDUSTRY. 

^   By  Sir  Edward  Sullivan,  Baronet.   (1870.)    8vo.       .    $1  5C 

ryiABLES  SHOWING  THE  WEIGHT  OF  ROUND,  SQUARE,  AND 
1    FLAT  BAR  IRON,  STEEL,  ETC. 

By  Measurement.    Cloth  63 

rpAYLOR. — STATISTICS  OF  COAL: 

^"  Including  Mineral  Bituminous  Substances  employed  in  Arts  and 
Manufactures  j  with  their  Geographical,  Geological,  and  Commer- 
cial Distribution  and  amount  of  Production  and  Consumption  on 
the  American  Continent.  With  Incidental  Statistics  of  the  Iron 
Manufacture.  By  R.  C.  Taylor.  Second  edition,  revised  by  S. 
S.  Haldeman.  Illustrated  by  five  Maps  and  many  wood  engrav- 
ings.   8vo.,  cloth     .       .  $6  00 

riPEMPLETON. — THE  PRACTICAL  EXAMINATOR  ON  STEAM 
A    AND  THE  STEAM-ENGINE  : 

With  Instructive  References  relative  thereto,  for  the  Use  of  Engi- 
neers, Students,  and  others.  By  War.  Templeton,  Engineer  12mo- 

SI  25 


HENRY  CAREY  BAIRD'S  CATALOGUE. 


23 


IHOMAS. — THE  MODERN  PRACTICE  OF  PHOTOGRAPHY. 

By  R.  W.  Thomas,  F.  C.  S.  8vo.,  cloth  ....  75 
«*PHOMSON. — FREIGHT  CHARGES  CALCULATOR. 

By  Andrew  Thomson,  Freight  Agent  .  .  .  .  $1  25 
TURNING :  SPECIMENS  OF  FANCY  TURNING  EXECUTED  ON 
*    THE  HAND  OR  FOOT  LATHE : 

With  Geometric,  Oval,  and  Eccentric  Chucks,  and  Elliptical  Cut- 
ting Frame.  By  an  Amateur.  Illustrated  by  30  exquisite  Pho- 
tographs.   4to  $3  00 

^TURNER'S  (THE)  COMPANION: 

Containing  Instructions  in  Concentric,  Elliptic,  and  Eccentric 
Turning;  also  various  Plates  of  Chucks,  Tools,  and  Instru- 
ments ;  and  Directions  for  using  the  Eccentric  Cutter,  Drill, 
Vertical  Cutter,  and  Circular  Rest ;  with  Patterns  and  Instruc- 
tions for  working  them.    A  new  edition  in  1  vol.  12mo.       $1  50 

TTRBIN  —  BRULL.—  A  PRACTICAL  GUIDE  FOR  PUDDLING 
U   IRON  AND  STEEL. 

By  Ed.  Urbtn,  Engineer  of  Arts  and  Manufactures.  A  Prize 
Essay  read  before  the  Association  of  Engineers,  Graduate  of  the 
School  of  Mines,  of  Liege,  Belgium,  at  the  Meeting  of  1865-6. 
To  which  is  added  a  Comparison  of  the  Resisting  Properties 
of  Iron  and  Steel.  By  A.  Brull.  Translated  from  the  French 
by  A.  A.  Fesquet,  Chemist  and  Engineer.    In  one  volume,  8vo. 

$1  00 

TTOGDES. — THE  ARCHITECT'S  AND  BUILDER'S  POCKET  COM- 
V   PANION  AND  PRICE  BOOK. 

By  F.  W.  Vogdes,  Architect.  Illustrated.  Full  bound  in  pocket* 

book  form   .       .    $2  00 

In  book  form,  18mo.,  muslin    .       .       ,       .       .  1  50 

WARN.— THE  SHEET  METAL  WORKER'S  INSTRUCTOR,  FOR 
VV  ZINC,  SHEET-IRON,  COPPER  AND  TIN  PLATE  WORK- 
ERS, &c. 

By  Reuben  Henry  Warn,  Practical  Tin  Plate  Worker.  Illus- 
trated by  32  plates  and  37  wood  engravings.    8vo.  .       .    $3  CO 

yn-ATSON.—  A  MANUAL  OF  THE  HAND-LATHE. 

"  By  Egbert  P.  Watson,  Late  of  the  "  Scientific  American,"  Au- 
thor of  "Modern  Practice  of  American  Machinists  and  Engi- 
neers,"    In  one  volume,  12mo.        .       .       .       .       .    $1  50 


24 


HENRY  CAREY  BAIRD'S  CATALOGUE. 


WATSON.— THE  MODERN  PRACTICE  OF  AMERICAN  MA. 
VY  CHINISTS  AND  ENGINEERS : 

Including  the  Construction,  Application,  and  Use  of  Drills,  Lathe 
Tools,  Cutters  for  Boring  Cylinders,  and  Hollow  Work  Generally, 
with  the  most  Economical  Speed  of  the  same,  the  Results  verified 
by  Actual  Practice  at  the  Lathe,  the  Vice,  and  on  the  Floor. 
Together  with  Workshop  management,  Economy  of  Manufacture, 
the  Steam-Engine,  Boilers,  Gears,  Belting,  etc.  etc.  By  Egbert 
P.  Watson,  late  of  the  "  Scientific  American. "  Illustrated  by 
eighty-six  engravings.    12mo.  $2  50 

WATSON.— THE  THEORY  AND  PRACTICE  OF  THE  ART  OF 

VV  WEAVING  BY  HAND  AND  POWER: 

With  Calculations  and  Tables  for  the  use  of  those  connected  with 
the  Trade.  By  John  Watson,  Manufacturer  and  Practical  Machine 
Maker.  Illustrated  by  large  drawings  of  the  best  Power-Looms. 
8vo.      "  $10  00 

niTEATHERLY. — TREATISE  ON  .THE  ART  OF  BOILING  SU- 
VV  GAR,   CRYSTALLIZING,    LOZENGE-MAKING,  COMFITS, 
GUM  GOODS, 

And  other  processes  for  Confectionery,  &c.  In  which  are  ex- 
plained, in  an  easy  and  familiar  manner,  the  various  Methods 
of  Manufacturing  every  description  of  Raw  and  Refined  Sugar 
Goods,  as  sold  by  Confectioners  and  others       .       .  $2  00 

ILL.— TABLES  FOR  QUALITATIVE  CHEMICAL  ANALYSIS. 

By  Prof.  Heinrich  Will,  of  Giessen,  Germany.  Seventh  edi- 
tion. Translated  by  Charles  F.  Himes,  Ph.  D.,  Professor  of 
Natural  Science,  Dickinson  College,  Carlisle,  Pa.    .       .    $1  25 

T7T71LLIAMS. — ON  HEAT  AND  STEAM : 

Embracing  New  Views  of  Vaporization,  Condensation,  and  Expan- 
sion. By  Charles  Wye  Williams,  A.  I.  C.  E.  Illustrated.  8vo. 

$3  50 

WORSSAM.— ON  MECHANICAL  SAWS: 

From  the  Transactions  of  the  Society  of  Engineers,  1867.  By 
S.  W.  Worssam,  Jr.   Illustrated  by  18  large  folding  plates.  8vo. 

$5  00 


OHLER.— A  HAND-BOOK  OF  MINERAL  ANALYSIS. 

By  F.  Wohler.  Edited  by  H.  B.  Nason,  Professor  of  Chemistry, 
Rensselaer  Institute,  Troy,  N.  Y.  With  numerous  Illustrations. 
12mo  $3  00 


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L.  B.  CAT.  NO.  1137 

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GETTY  CENTER  LIBRARY 


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